Is DNA Evidence Foolproof?

[londonblue]

Not according to this:

BBC

 

[OldBlueLady]

Interesting you posted that because I finished that John Grisham book last night!

 

[londonblue]

Interesting you posted that because I finished that John Grisham book last night!

Good on you for reading it.

 

[Massimo Giovanni]

There are different levels of DNA, so the answer is;- depends!

Similar with fingerprints too, some can be partial and need corroboration when put before a court as part of the evidence.

Incredibly most parts of a human are individual; such as retina scans, tooth records, palm prints, even ear outlines.

 

[londonblue]

There are different levels of DNA, so the answer is;- depends!

Similar with fingerprints too, some can be partial and need corroboration when put before a court as part of the evidence.

Incredibly most parts of a human are individual; such as retina scans, tooth records, palm prints, even ear outlines.

Also interestingly a friend of mine has had a bone marrow transplant because he has had cancer twice and the doctors wanted to kill off his immune system and replace it with a donor's. That now means that his blood has different DNA to the rest of him. I joked and said he could get away with murder.

The strange thing is the same circumstances were used in the Undeniable TV mini series that has just been shown on ITV.

 

[Massimo Giovanni]

Blood is only part of DNA, it would not alter his hair, saliva, skin and I believe his blood will renew and refurb itself in a svery short period of time.

 

[Gremlin]

There are different levels of DNA, so the answer is;- depends!

But I suppose that, with reference to the article, all of them are only as good as the conditions they were captured under.

I remember having a ding-dong with someone on here a while ago who told me that, in their opinion, incriminating DNA evidence in a murder case should open up the possibility of capital punishment being applied. I couldn't be bothered to argue.

 

[londonblue]

Blood is only part of DNA, it would not alter his hair, saliva, skin and I believe his blood will renew and refurb itself in a svery short period of time.

His blood will never "refurb". It will always have a different DNA. Personally I think that's a bit freaky, but he was cool with it. Which isn't really a surprise because he has to live with it. In fact, if he didn't live with it, he'd quite literally be dead.

But yes, the rest of him will have his old DNA.

 

[A Century United]

Finger print evidence is far from foolproof even with complete prints. It has been demonstrated that if the FP expert knows who is looking to match the print with from the outset, he is more likely to find a match.

The Shirley McKie Case is an interesting example of both the possibility of Fingerprint Experts misidentifying prints, and of the lengths that they will go to, to defend their opinions (because a fingerprint identification is, ultimately, a matter of opinion).

 

[Massimo Giovanni]

Finger print evidence is far from foolproof even with complete prints. It has been demonstrated that if the FP expert knows who is looking to match the print with from the outset, he is more likely to find a match.

The Shirley McKie Case is an interesting example of both the possibility of Fingerprint Experts misidentifying prints, and of the lengths that they will go to, to defend their opinions (because a fingerprint identification is, ultimately, a matter of opinion).

Are you thinking of the partial scenario?
Partials are open to interpretation and challenge for the number of match points and probability/possibility of other persons having similar, limited prints.
A full, is a full, unarguable match.

 

[londonblue]

Interesting you posted that because I finished that John Grisham book last night!

Not that it should be on this thread, but you didn't tell us what you thought of the book.

 

[OldBlueLady]

Not that it should be on this thread, but you didn't tell us what you thought of the book.

Have commented on the "What are you reading one", though probably should have dug up the thread where you recommended it really! I enjoyed the book, it was very thought provoking, BUT, it didn't change my view. He was let down by a failure in AMERICAN law, not British. I still believe that people who commit serious multiple crimes (murder, rape) that they are absolutely without any shadow of a doubt guilty of, should forfeit their own life by way of punishment. And don't even get me started on that murderer **** who has just been awarded compensation for something prison officers are alleged to have broken and/or lost!!! :angry:

 

[maninasuitcase]

But I suppose that, with reference to the article, all of them are only as good as the conditions they were captured under.

I remember having a ding-dong with someone on here a while ago who told me that, in their opinion, incriminating DNA evidence in a murder case should open up the possibility of capital punishment being applied. I couldn't be bothered to argue.

I remember seeing that too, but even if DNA evidence is an exact 100% science it doen't discount the possibility that evidence could be planted or cross contamination could have taken place.

I'm with you on that one Gremlin, DNA evidence should never be used as an arguement to bring back capital punishment.

 

[londonblue]

Have commented on the "What are you reading one", though probably should have dug up the thread where you recommended it really! I enjoyed the book, it was very thought provoking, BUT, it didn't change my view. He was let down by a failure in AMERICAN law, not British. I still believe that people who commit serious multiple crimes (murder, rape) that they are absolutely without any shadow of a doubt guilty of, should forfeit their own life by way of punishment. And don't even get me started on that murderer **** who has just been awarded compensation for something prison officers are alleged to have broken and/or lost!!! :angry:

He wasn't let down by American law, he was let down by people. People are the same the world over.

 

[united we stand]

Have commented on the "What are you reading one", though probably should have dug up the thread where you recommended it really! I enjoyed the book, it was very thought provoking, BUT, it didn't change my view. He was let down by a failure in AMERICAN law, not British. I still believe that people who commit serious multiple crimes (murder, rape) that they are absolutely without any shadow of a doubt guilty of, should forfeit their own life by way of punishment. And don't even get me started on that murderer **** who has just been awarded compensation for something prison officers are alleged to have broken and/or lost!!! :angry:

I completely understand your point, and in a perfect world I actually agree with you in principle . But we live in an imperfect world if they are found guilty , they are found guilty -- and this is where this whole argument breaks down. Added to this is the fact that mistakes can and do happen . I have run through this in my mind several times and keep asking myself the question 'At what point is someone 100% guilty and at what point are they 99% guilty. I could never agree with executing someone that was 99% guilty . At that point a lawyer will argue that at 99% guilty there is reasonable doubt, and therefore they are not guilty, so you end up with a circular argument that everyone found guilty of murder could potentially be executed- and that to me is wrong

 

[londonblue]

I completely understand your point, and in a perfect world I actually agree with you in principle . But we live in an imperfect world if they are found guilty , they are found guilty -- and this is where this whole argument breaks down. Added to this is the fact that mistakes can and do happen . I have run through this in my mind several times and keep asking myself the question 'At what point is someone 100% guilty and at what point are they 99% guilty. I could never agree with executing someone that was 99% guilty . At that point a lawyer will argue that at 99% guilty there is reasonable doubt, and therefore they are not guilty, so you end up with a circular argument that everyone found guilty of murder could potentially be executed- and that to me is wrong

This is what Pubey was alluding to. The burden of proof for a civil case in the country is balance of probability, i.e. more than 50%. The burden of proof for a criminal case is beyond reasonable doubt. That means that anyone can be convicted of murder (or of any criminal act for that matter) if the jury is, say, 90% sure they're guilty.

For OBLs argument to make sense you would have to change the burden of proof to be 100%, and that would mean that most people would never be convicted of anything. Even if you made it 100% only for murder trials, then I doubt anyone would ever be convicted of murder again. And even when a jury is 100% sure they may still be found to be wrong in the future for various reasons such as new evidence that wasn't originally available, and police withholding evidence. (I'm sure a criminal lawyer would be able to come up with many more reasons...)

Going back to the Barri White case you highlighted. It seems odd to me that he was convicted, and the DNA evidence on the steering lock ignored even though it had been taken (and which eventually proved his innocence and someone else's guilt), and obviously wasn't a match to him or his friend. If the police were doing their job that would not have been overlooked. It would have set alarm bells ringing. The police followed normal human behaviour: they ignored evidence that didn't fit their story. However, a policeman shouldn't do that. They should find a story that matches ALL the evidence, and it is simply wrong not to do so. Either they were lazy, or wanted/were under pressure to secure a conviction. This will always happen because, as you say, this isn't a perfect world, and even DNA evidence doesn't prove something 100%.

 

[londonblue]

Deleted by me!

 

[Gremlin]

Even if you made it 100% only for murder trials, then I doubt anyone would ever be convicted of murder again.

I suppose you're only thinking of those entering a Not Guilty plea!?

 

[davewebbsbrain]

Also interestingly a friend of mine has had a bone marrow transplant because he has had cancer twice and the doctors wanted to kill off his immune system and replace it with a donor's. That now means that his blood has different DNA to the rest of him. I joked and said he could get away with murder.

The strange thing is the same circumstances were used in the Undeniable TV mini series that has just been shown on ITV.

I saw that too, was a very good drama, as are most ITV dramas recently, much like Prey looks like it will be top class too.

I digress though. The fact they used the bone marrow thing with the blood being different string to the other DNA of the guy was really rather interesting. I guess this is true in real life and not just fiction for the TV show.

 

[A Century United]

Are you thinking of the partial scenario?
Partials are open to interpretation and challenge for the number of match points and probability/possibility of other persons having similar, limited prints.
A full, is a full, unarguable match.

A full print is still ultimately a matter of opinion. The FP expert is looking to match 6 or more points between prints to prove that they are identical. The idea that they can take a full print and sort of hold it over the comparison print and declare a match isn't true. Prints from the same finger leaving prints at different angles with different pressure on different surfaces at different times will never be completely identical. The infallibility of finger print evidence has been touted for years, but it is nowhere near as reliable as people think.