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Should we allow relative's DNA matching to prove innocence?

Earlier I wrote about the ability to find you from a DNA sample by noting it's a near match with one of your relatives. This is a concern because it means that if relatives of yours enter the DNA databases, voluntarily or otherwise, it effectively means you're in them too.

On a recent 60 minutes on the topic, they told the story of Darryl Hunt, who had been jailed for rape and murder. It wasn't clear to me why, but this was done even though his blood type did not match the rapist's DNA. Even after DNA testing improved and the non-match was better confirmed, he was still kept in jail, because he was believed to be the murderer, if not the rapist, ie. an accomplice.

Later, they did a DNA search on the rapist's DNA and found his brother in the database, who had been entered due to a minor parole violation. So they interviewed the brothers of the near-match and found Willard Brown, who turned out to be the rapist. Once they could see he was not an associate of the rapist, Hunt was freed after 19 years of false imprisonment.

The piece also told the story of another rapist, who had raped scores of women and stolen their shoes as souvenirs, but had become a cold case. He was caught because his sister was in a DNA database due to a DUI.

Now much of our privacy law is based on having your own private data not seized and used against you without probable cause. It's easy to answer the case of the shoe rapist. There are a wide variety of superior surveillance tools we could allow the police to use, and they would help them catch criminals, and in many cases thus prevent those criminals from committing future crimes. But we don't give the police those tools, deliberately, because we don't want a world where the government has such immense surveillance power. And a large part of that goal is protecting the innocent. Our rules that allow criminals to walk free when police do improver evidence gathering and surveillance to catch them are there in part to keep the police from use of those powers on the innocent.

But the innocent man who was freed presents a more interesting challenge. Can we help him, without enabling 1984? In considering this question, I asked, "What if we allowed DNA near matches to be used only when they would prove innocence?" Of course, in Hunt's case, and many others, the innocence is proven by finding the real guilty party.

So what if, in such cases, it was ruled that while they might find the guilty party, they could not prosecute him or her? And further, that any other evidence learned as a result was considered Fruit of the poisonous tree? That's a pretty tough rule to follow, since once the police know who the real perpetrator is, this will inspire them to find other sorts of evidence that they would not have thought to look for before, and they will find ways to argue that these were discovered independently. It might be necessary to put on a stronger standard, and just give immunity to the real perpetrator if sufficient time has passed since the crime to declare the case to be cold.

Setting out the right doctrine would be difficult. But if it frees innocents, might it be worth it?


You say: Our rules that allow criminals to walk free when police do improver evidence gathering and surveillance to catch them are there in part to keep the police from use of those powers on the innocent. Almost. The rules are the to keep the police from misusing those powers on the innocent. But you haven't outlined the misuse scenario. And I'm not sure you can -- at least, I can't see what the problem might be. Imagine a case where you have, say, security cam pictures of a crime, and you canvass neighbors of the crime scene for information about who's in the photo. I don't think there's anything wrong there. Similarly, canvassing a DNA database for for phylogenetic neighbors of a given sample strikes me as innocuous, assuming, of course, perfect reliability of the technical processes involved.

I agree with you, but you have to realise that Brad is at the extreme end of
the political spectrum, i.e. he is an extreme libertarian. I live in a country
where personal ID cards are mandatory. Brad fights these like they would signal
the end of the world. My point of view: no innocent person ever has a need to
conceal his identity.

There are countries where every citizen gets a number at birth which is used on
ALL public records, making cross-correlation very easy. In those same countries,
every citizen can see the tax return of every other citizen---there doesn't even
have to be a reason given.

And how do these countries fare in terms of things which really matter, like
personal freedom, human rights, low crime, avoiding wars? MUCH, MUCH better
than more libertarian countries like the US or Canada.

Basically, if one has to enact laws to prevent the government from misusing power,
then one has already lost in that a government which would want to misuse its power
is the wrong government.

Extremism also depends on context. In many societies resistance to universal ID cards is not considered extreme at all. And fortunately many folks still realize the great fallacy of "No innocent person ever has a need to conceal his identity."

But I'm afraid it's hard to see how any correlation you might find between high surveillance societies and avoiding wars is unlikely to be causal. Having less crime I can certainly see a link. However, it is about personal freedom and human rights that we are having a debate.

"Extremism also depends on context. In many societies resistance to universal ID cards is not considered extreme at all."

Of course. For the Taliban, requiring women to wear the burka isn't considered extreme at all. Probably, no-one
considers HIMSELF an extremist; the only scale is comparison with other people.

A society which has lots of surveillance goes hand in hand with a society which trusts its government. (I'm not
talking about totalitarian police states, but rather democratic societies (really democratic, with several parties,
PR etc) whose population WANTS surveillance.) It also goes hand in hand with people trusting each other. I think that
in many cases, the extreme individualism (libertarianism) at the personal level, "me against the world", translates
into "my country against the world". People happy to live near, in many senses, to each other tend to be more
concerned about the world living together.

But, where is the problem. Suppose there is a crime and the police send an SMS to everyone who was near the
scene of the crime when it happened, asking for helpful information. What's wrong with that? Where is the
CONFLICT betwwen giving the police more power and personal freedom---except the personal freedom for the guilty,
of course?

What if the police ask for DNA samples from everyone near the scene of the crime? Why not? What does an
innocent person have to lose. Since no-one equates being near the scene of the crime with suspicion, why not
check everyone---if the DNA doesn't match, no problem, but it might help to find the guilty party. Why not
have a database of every person's DNA, fingerprints etc? It WOULD help catch criminals. How can it possibly
have an adverse effect on the innocent?

Of course, if you are thinking about the danger that your health insurance might drop you if they realise
you have some genetic defect or whatever, then I can only say that a country which doesn't have state health
insurance for everyone, full stop, is beyond repair anyway.

The idea the innocent have nothing to hide keeps coming up, so I will have to write about it more in the future, but here's a pointer to a recent essay.

This comes up frequently. The common example given is the "partial match" on a licence plate allowing the police to go investigate all the drivers in the partial match set.

DNA and car licence plates are very different. DNA is hugely personal and descriptive of you. As I've noted, in time, technology will be able to map from DNA (and even partial DNA) to an excellent physical description, a drawing better than a typical police sketch, and probably a good medical evaluation too. It's our software, but we can't help shedding it. It's a special case that we must seriously consider extraordinary rules about how public it will be. Normally we say "If you go out in public, give up some privacy" but DNA is so detailed that it's more akin to a diary you can't avoid dropping copies of everywhere you walk. That we shed DNA is a fact of reality; our rules will take the unusual step of trying to get us back to where we were when we couldn't read it.

Because of this there are rules about how and when they can take your DNA (usually a conviction, though in some places just an arrest) and how they can store and use it. For example, U.S. federal law does not allow the FBI to do this sort of partial matching of relatives, but some state laws do, which is why these cases arose.

It's important because it means you're in the database even if you fought not to be in it. Your own cells can be used to betray you in spite of all your efforts. You can become under surveillance in spite of trying to keep private, because your brother or cousin didn't. This is the principle being protected.

And no, the privacy rules don't just stop the police from "misusing" their powers on the innocent. In many cases, any use of those powers on the innocent (or rather those for whom there is no probable cause) is considered misuse. In fact, use of surveillance powers on the guilty without meeting the appropriate standards of probable cause or suspicion is considered abuse -- innocence does not play a role. What is true is that we know if the standards are not being met on the guilty, they are also not being met on the innocent.

The key difference in technology/surveillance issues is scalability. Canvassing neighbours requires human legwork. It doesn't scale. There is an inherent limit on state power. Technological surveillance, including DNA database scanning, scales. One human can check lots of samples against millions of database entries just as easily as checking against one database entry. When new forms of surveillance scale like this, it often results in a shifting of the balance between state power and the freedom of the individual, and we must examine this shift and decide if it should be corrected for.

It is not hard to shift the balance in a variety of ways, which would give the police the ability to catch more criminals at some cost in civil rights. That's an ancient debate. We could have everybody wear a GPS transponder (half of us carrying them now voluntarily) and have the police be able to know everybody who was near a crime scene. This would solve a lot of crimes, but is it the sort of power you want to give the police? The type of society you want to live in?

And no, the privacy rules don’t just stop the police from “misusing” their powers on the innocent.

Of course. But the reason for the rules is to forestall abuse of innocents. We draw a broad line because the end never justifies the means. But in the absence of a case where innocents can be abused, there can be no reasonable justification for handcuffing the police. All of your arguments amount to "I didn't do anything, so I don't want them to be able to check whether I did." But the problem only arises if it's possible that you didn't do anything and they come after you anyway -- it's the likelihood of false positives that raises the civil liberties issue, and that's what you haven't made a case for.

False positives are important, but they are far from the only thing.

First, a society that is aware it is under surveillance feels less free and people act less free, subjecting themselves to self censorship. See [[b:watched.html|A Watched Populace Never Boils]].

Secondly, effectively all surveillance technologies get repurposed and used for new activities, frequently pernicious ones. You have to in fact make the presumption of misuse. This applies not just in the country that first implements the technology.

You must also consider that once developed, it will be exported to countries with even worse civil rights records. (Example: U.S. Law requires Cisco to put wiretapping code into routers. Routers are then exported to China, Saudi Arabia, and even Greece.) Do we have any moral duty to consider what will happen if the good guys build surveillance infrastructure and then the bad guys find it easier to obtain or deploy?

There is only one solution, history teaches us. Minimal development and deployment.

The country with the best civil rights protections sets the bar for the world. It's well know that when the US, considered a bastion of free speech, adopts a restriction on free speech, the rest of the world starts arguing, "Well, if the USA can do this, and they're nuts about free speech, surely we can too."

Early on we asked the question, "Should the government have a big DNA database of anybody, so that if they get a DNA sample they can find who it is?" and so far the answer has been "no." Does the technology to spot relatives, which effectively gives us the quivalent of a DNA database of anybody, change our answer to that question?

If you're concerned about misuse of a DNA database, you should be arguing that the DNA database shouldn't exist at all, not that we should have a bunch of silly rules about how it can or can't be used. Bush's cronies, or the equivalent, are ignoring the rules already; they're hardly going to care about one more rule to ignore.

In the specific case that a crime has been committed, and the police have a DNA sample that they are 100% certain belongs to someone at the crime scene? I think they should use whatever data they can get their hands on, and I'm perfectly fine with tracking people via their relatives as long as it doesn't cause trouble from false positives.

I sort of agree with you that maybe the government shouldn't have a DNA database. But your poisoned-fruit rule would hamper the "good guys" without inconveniencing the abusers at all.

Police are never 100% certain or 100% right, that's why we have all these rules about 'em.

For better or worse, we have a DNA database. The law decided that if you were convicted (or just arrested) you could be forced to hand a sample over and be put in the database. There was quite a bit of argument over that, and while it would be nice to re-argue it, that's not happening right now.

We did not decide we were putting your whole family in the database. Now we are learning this is a consequence. (And since the black population is over-represented among those convicted and arrested, it means we end up with a large proportion of black people "in" the database compared to whites or other groups.)

You seem to be saying, "We accepted a database of felons, so now you might as well accept a database of everybody because if now flows from a database of felons." But we didn't accept a database of everybody.

Note that we *could* design the databases to only return exact matches. There are hashing techniques that should be able to do that.

"The country with the best civil rights protections sets the bar for the world. It's well know that when the US, considered a bastion of free speech, adopts a restriction on free speech, the rest of the world starts arguing, "Well, if the USA can do this, and they're nuts about free speech, surely we can too.""

Are you seriously suggesting that the US has the best civil rights protections in the world? Ever heard
of Guantanamo?

Better than Iceland, Finland, Sweden, Norway, the Netherlands, Germany, Austria? Come on!

These are tragedies. No, the US does not have the best civil rights protection, though probably the best free speech protection of the major nations. But my point is that whoever is the best defender has to maintain it, as their slips are mirrored around the world. We need fewer Guantanamos, and if that doesn't convince you we want to limit the surveillance powers of the USA, I am not sure what else will.

"We need fewer Guantanamos, and if that doesn't convince you we want to limit the surveillance powers of the USA, I am not sure what else will."

I don't see any connection at all. Guantanamo is not about surveillance, it is about
incarcerating people without due process. This is a straw-man argument, along the
lines of "ID cards lead to Guantanamo". (I just mentioned Guantanamo to point out that
the U.S. is not a bastion of civil rights.)

Actually, surveillance could have HELPED here, since one could say "if the surveillance
is so good, only those actually observed committing a terrorist act need to be dealt
with". (Of course, they should still be dealt with in a sensible manner.)

In England, ID cards are very controversial. England, or at least the government, supported
the USA in the "war on terror". Countries like Germany and France, with mandatory ID cards,
were very vocal critics, prompting the "old Europe" epithet.

A couple of decades ago, when machine-readable ID cards and passports were introduced in Europe,
some libertarian types said that's bad, since if some country becomes Fascist or whatever,
then we can just fake ID cards and get people out of the country. Yeah, man, real realistic,
like the armed thug says "I want to detain you or even shoot you, but since we don't have
machine-readable passports, I can't tell if yours is fake or not, so I'll just have to let
you pass".

Bottom line: a government which needs to have surveillance powers limited for fear that they might
be abused, will find other ways to violate civil rights. Again, the U.S. is a good example.

As Henry Kissinger said, the illegal stuff we do right away, the unconstitutional takes just a bit

I am not saying that ID cards lead to guantanamo. I use it as an example of what Kissenger was talking about. How easily important rights will be trampled in the event of crisis.

Civil rights advocates know that in good times, you don't have to worry so much or work so hard to protect rights, because the danger is much less then. But the good times are atypical in history, and not just ancient history -- which the Europeans know better than the Americans.

Those European libertarians were saying, "When the fascists try to return, and they will, do we want to have a surveillance infrastructure in place for them? Just to make it easier for today's bureaucrats to do tracking today that seems more benign?"

Guantanamo shows where even a nation with a strong tradition and constitution can go overnight when the wrong events happen.

I must say I find it amusing you feel the desire to participate in this thread anonymously.

There are a whole series of issues around DNA evidence. DNA isn't an absolute identifier. Like fingerprints, there's a misconception about just how accurate it is - most people think that fingerprints and DNA can tell you that unidentified Person A is definitely the same person as Suspect 1. Rather, we need to think of it as being able to tell you that Person A is definitely not Suspect 1. Looking for similarities in two potentially related patterns can be misleading, as it's possible then to ignore the differences and distort your conclusions. It's much more accurate to look for differences to rule people out.

Misidentification does happen, this isn't just a hypothetical situation.

Here in the UK, we have a massive DNA database, created and administered by the police. It has one in 10 of our white males listed, but four in 10 black males. There are also a scarily huge number of children on the database, as well as witnesses (i.e. people who were never even suspects), people who've given DNA samples in order to have themselves ruled out, people who have been acquitted, and those who were never charged. Once you're on the DNA database it's nigh on impossible to get off - your details will be kept for 100 years.

There's no doubt that DNA evidence can be useful indeed, but if you have a large database which you trawl for matches, it's possible for the police to find a match and then construct a case where there is none. We've seen this with fingerprints, and I'm sure that there are or will be examples based on DNA too, where innocent people find themselves in jail because their DNA happens to be similar to the person who actually committed the crime.

The problem with proposing a 'proving innocence' rule would be that the police would never go for that sort of restriction of their power, regardless of which country they are in. They see this as evidence - which is it, used properly - and any fruit of the poison tree proposal would never fly.

In Hunt's case, it seems from your description that the justice system was flawed in the first place - he was incarcerated despite contrary evidence. Plus overturning convictions always seems to be a bit of a problem, I suspect because it means that the authorities made a mistake and there's resistance from them to admit that. So is the problem here that there wasn't accurate enough enough DNA evidence in the first place, or that it was misused, or that the system itself was flawed?

The problem with having a big DNA database goes beyond the issue of whether the police correctly use the evidence to corroborate rather than as a central pillar of their case. Once you gather lots of data about people in one spot, all sorts of things become possible. Corruption, such as selling data illegally, becomes possible and again, we've seen this happen in the UK with the National Police Database. Identity theft is bad enough if your credit card details are nicked - but you can get new cards. You can't exactly get new DNA.

There's mission creep, where increasingly wide uses are authorised, such as racial profiling or the identification of men accused of not paying paternity support.

And there's the problem of the mass criminalisation of society - treating everyone as if they are a suspect undermines trust in the police and government, which has some pretty nasty knock-on effects in terms of damaging the fabric of society and the relationship between people, particularly young males, and the authorities.

Overall, I think that we (i.e. all countries using DNA evidence) need to have a clearer understanding of exactly what DNA evidence means, what it can and cannot do, the risks of using it, and under what circumstances it can mislead. We need to resist building big databases of DNA samples, no matter how attractive that seems. And we need to stress the importance of corroborating evidence - no one should be convicted by DNA alone.

If you're interested, the Open Rights Group (disclaimer: I started it!) in the UK has a lot of good stuff on its wiki about this and related issues:

While there can be some debate about the accuracy of current DNA sampling techniques and database matching techniques, I have little doubt that this technology will improve to the point it can perfectly tell if two people are not the same, and that they are the same. It's a great deal more detailed than fingerprints. Indeed, before too long DNA samples will allow them to produce a decent physical description of you.

As such, in considering these issues, I am looking at the long term view, when the tech becomes even better, though until it is, we should be wary of mistakes as you say.

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