Schneier on Security

Clive Robinson • December 20, 2010 4:00 PM

The main problem with forensic evidence (other than the CSI effect) in court is “it’s not the evidence” but “reports on the evidence” that are examined.

I’ve said ir before (and yes it’s an over generalisation) but Judges understand and judge paper not evidence.

There was a case in Scotland of a police woman’s fingerprint supposadly turning up in a crime scene and she was part of the perimiter guard but claimed she did not actually go into the crime scene thus could not account for how her fingerprint got there.

She lost her job it went to court fingerprint experts from the police lab claimed it was a good match etc. The judge accepted their word.

Only the claims where false it was not her fingerprint at all. When it went back to court the forensic people only showed a small part of the print found and her print, but they where not a good match. When the full print found was seen it was obvious to a lay persons eye it was not here print.

To this day the fingerprint service involved will not admit in any way they made a mistake.

And this is the point we don’t chalenge the actual evidence only reports on the evidence that are supposed to be impartial and independant (and invariably arn’t).

If an expert witness can not show all of the evidence and take a jury through it clearly then it’s not evidence because the burden of proof requirment is not met.

But everyday in every country there is this problem of “evidence” that is actualy a “report” being waved through a court because the judge is overly reliant on the expert witness being supposadly independent unbiasd and forthright with the court.

In most cases it probably does not matter but in some it’s crucial and for a judge to not allow agressive cross questioning of expert witnesses because “it might confuse the jury” is a very sad state of affairs.

As one judge once put it “there is a golden thread of truth” that runs through every case it should not be alowed to be spun and cast into Gordian knots by unchalleged Expert Witnesses just to save a little confusion of one or both of the tribunals, for if it is justice is not served.

Clive Robinson • December 22, 2010 4:18 AM

@ Tyler,

“In the case of computer forensics, how does the defense and jury know that the defendant’s storage devices haven’t been modified by the examiners to aid in conviction?”

If you have not taken certain precautions in advance then it’s a case of how inept they are and not just how skilled you are but how much time you get to examine the “evidence”.

And it is this time factor prosecutors are using. They withold the evidence from the defence untill the last possible moment and as in one case in the UK involving complex financial records across seven companies, tell the Judge that the defence could “examine the books with a calculator over night” and the Judge accepted it…

When you have idiocy of that magnitude on the bench justice will not be in any way served.

And you might be asking why the prosecution was so keen to procead with the upmost unseamly haste. Well it appears that the prosecution did not actually have a case. But under the UK Proceads Of Crime Act (POCA) that they had invoked not only did they strip the defendant of his rights but they where also going to get a significant percentage (about 1/5) of any assets taken from the defendant.

Just another reason to believe that the UK is a “hollowed out country” where those at the top make sure that there is no justice for the ordinary man.