Computers, Court, and Fingerprints

Degrees writes "Should Law Enforcement be allowed to Photoshop fingerprints? That is the question posed in this article in the South Florida Sun-Sentinel. The suspect is charged with murder, and the evidence was circumstantial before the fingerprint enhancment. At the end, the crime scene investigators say they want encrypted cameras. The implication is they want DRM-enabled digital cameras with software for full audit-trail capability. Would that make the Photoshoping more credible? Would DRM cameras be a good thing for Joe Citizen?"

Comments

The glove didn't fit

[CrazyDwarf]

I've always wondered about cases where digital evidence was envolved. We have no way of knowing if the files are tampered with or otherwise altered, and I really doubt they'd let us compare (in this case with actual fingerprints.)
I think that guy that was on trial recently for the disappearance of that girl didn't surf for child porn, the cops did... then changed the dates on the files to cover their own butts.

I saw this on tv

[LennyDotCom]

I saw this on the discovery channnel I think they showed how all the cop did was enhance the image with photoshop. All he did was apply a custum filter to enhance the image he didn't add anything to it or change it just brought out what was there by filtering out the background. I was very obvious if you saw the show that it should be perfectly legal .

Useful... possibly

[rworne]

The only way this can be seen as useful is if the person who is "cleaning up" the fingerprint has no idea who the print belongs to and where the print came from. Considering all the prints the law enforcement must deal with, it would be hard to assume the print a tech is working on is for a high profile murder suspect or a car thief.

That way it removes the ability to "doctor" prints to match what the cops want, and it adds a valuable tool to the investigative process.

If this process involves the tech working on a print, with the "target suspect" print available to him, I'd cry foul in an instant.

How to stop this method from working in court...

[Brightest Light]

One of the biggest questions about the new technology is: Could a skillful technician create or copy a suspect's fingerprint and frame someone by making it look like that fingerprint was at a crime scene?

Here's an idea: Get a copy of the print image, find somebody with Photoshop skill, get them to alter the image to show judge's/prosecuting attorney's/etc's print; evidince (hopefully) supressed when the judge realizes how easy it is to fake 'evidince' that way.

Any evidence can be tampered with

[stratjakt]

Thats why the term is 'reasonable doubt'. The DNA technician can lie. The blood can be planted. You can doctor an analog photo just as easily.

I've mentioned before that I design, write, and support police records software. I know how important audit trailing is to them, I was up until 3 AM last night debugging some of it.

We've even been approached with this very idea, audit trailing and securly storing digital photos. (Not just fingerprints)

This is about showing a factual list of who had access to the photo, exactly what they changed, and when. If pixels were added, it'd be on the trail. If it was lightened, darkened, it'd be on the trail.

The reason is simple. The jackass lawyers who think the constitution spells out their job as 'get the client off, no matter what it takes'. Another rant entirely, but rigorous defence doesnt mean knowingly lying and misleading a jury.

Police are constantly accused of lying, tampering with evidence, planting evidence, in stupid cases like misdemeanor posession of pot.

So when Mr Defense gets up in front of the jury, with Mr Cop on the stand, and says "Isn't it true that anyone could have altered those photos?", "Mr Cop can say, here's an itemized list of every enhancement, change, and view of the photos since they were taken.".

If Mr. Defense is stupid enough to continue, they can present sworn depositions from people like me (who created the system) testifying to the authenticity of the data.

Of course - it'd go both ways. If Mr Defense truly thinks BeatCop O'Malley doctored the photos, someone like me could likely prove the when and how.

This isn't a bad thing, or about stripping rights. It's about helping to secure the right to a fair trial.

Re:"Enhanced" evidence

[sacherjj]

Can't you look at the enhanced and unenhanced and verify that it is the same print? To me, enhancement can be considered part of the collecting, sort of like a filter that may exist in an audio recorder. If new ridges were not drawn, is this truly "doctoring" the print? I agree that it is a slippery slope and the determination has to be the level of enhancement. Can it still be considered a cleaned up version of the original, or did the enhancement add new ridges, etc. to the print?

Keep Film Cameras

[mbstone]

In the People v. O.J. Simpson case, Simpson's lawyers demanded the contact sheet from the police crime scene photos. They didn't get the contact sheet -- which conclusively reveals the order in which the photos where taken -- until the trial was nearly over:

THE COURT: The court will entertain a motion to shorten time. All right. Any other Brady issues we need to discuss?

MR. SCHECK: There is the matter of the contact sheets.

THE COURT: I'm sorry?

MR. SCHECK: The contact sheets.

THE COURT: All right.

MR. SCHECK: We believe, your Honor, that the testimony yesterday of the other--this week of Mr. Rokahr is extremely significant. It is significant because it establishes that the picture of Detective Fuhrman pointing at the glove occurred at night, not at 7:00 in the morning or about an hour and a half after daybreak. More significantly, it puts Detective Fuhrman in an area by the evidence at a time when he is unsupervised or unobserved, I should say, by others, and it is in complete contradiction not only with his testimony, but an apparent contradiction with the testimony of other officers. The pictures speak for themselves and are extremely powerful evidence.

Now, the problem that we've had in this case, as the court is well aware, is that we have been requesting, A, a photo log or a listing of the order and/or time that pictures were taken, or B, an opportunity--or contact sheets, or C, an opportunity to make contact sheets to the negatives. This was pursued in discovery in pretrial and it was pursued during the trial. Now, Miss Clark got up here yesterday and said that she was able to look at the photographs and see numbers on the face of the photograph and she herself had put together a stack of the photographs in order so that she knew the sequence. Well, that is something that Dr. Lee, Dr. Wolf, Dr. Baden, myself, the other lawyers on this team, could not do for a number of reasons. No. 1, there are different photographs--photographers in this case and the numbers--there were more than one, for example, picture no. 35. No. 2, as the court noted and Mr. Rokahr noted in some of these pictures, the--you can't see the number. And most important of all, your Honor, as the court noted itself yesterday, the best proof, the real proof as to what pictures were taken in what order are the numbers on the Kodak print. That is the real proof. That is the hard-core proof.

THE COURT: Frame number on the film.

MR. SCHECK: The frame number on the negatives. Now, the problem I have, and I mentioned it to Mr. Hodgman yesterday, is that Mr. Hodgman is the lawyer and then later Mr. Yochelson, who was designated to be dealing with discovery for the Defense. And this court is aware, and Mr. Hodgman has conceded candidly with this court, that they had no photo logs, they had no ordering of pictures, that they did not believe, until we discovered this contact sheet from Bodziak, that these contact sheets could be made from the negatives, that there was no ordering. I am very, very troubled by the fact that Miss Clark is telling this court yesterday that she had a list of photographs and an ordering. Well, if she had it and they were determined--they had determined--she had determined through conversations with photographers or detectives on this case, that she knew which pictures were taken in which order, then we are being misled because we are only dealing with Mr. Hodgman and Mr. Yochelson who know of no information in the District Attorney's office or in law enforcement that contain an ordering of the photographs.

Enhancing Evidence

[cosyne]

Image transforms do not add information to an image, they just make it easier to see the information which is there (try using Photoshop Auto-level to make an image of bill clinton shaking hands with an alien). Using dodge and burn over an entire image or a large area of it will not let you change fingerprints, just make existing ones easier to see. However, if you go into photoshop and use a one pixel burn brush you could draw lines with it. This is why it's important that the person doing the image processing isn't also doing the fingerprint analysis. It's like medical imaging- the imaging tech generates a good image, the doctor decides what it means.

As for the 'As if by magic' and 'psuedo-science' bits in the article, those are irresponsible hype. It's like saying you expose film in a camera, develop it, and an image appears as if by magic. If you didn't know how a TV worked, you'd think that was magic too. As for the unrepeatability of results, no two people using fingerprint dust will get exactly the same results. Same with a photoshop brush. If you brushed the same areas in the same ways, you'd get the same results, otherwise not. Duh.
This does bring up a point of repeatable, localized image processing. My guess is it wouldn't be too hard to get the GIMP to record all brush strokes. It surely stores their results for the undo option. How hard would it be to output an XML encoded series of operations along with the output image? Then if there's any question as to the usability of the results, someone can start with the original image and apply the same set of operations one at a time. Maybe add image cryptosigning, and sell linux+gimp boxen as forensics tools.
Finally, i'm surprised there isn't a standard government issue image transform system. NIH Image might be a good place to start, or just a front end to matlab's image processing toolbox which is luser-friendly and keeps usable, crypto-signable records of each transform it does. As long as there aren't any brushes, no expert witness in image processing is going to say you could doctor prints.

Re:"Enhanced" evidence

[CaseyB]

Such digital enhancement might be useful for getting leads, but the result isn't evidence; it's just a computer-assisted guess.

Applying, say, a contrast filter to a digital image to bring out details is no different from the subjective treatment that a conventional photograph gets when developed in a darkroom.

I imagine that the various tests that forensic scientists perform are rigorously standardized. There's no reason that digital processes couldn't be similarly regulated. I supposed what is called for is the certification of "official" digital filters, that are analyzed and confirmed to manipulate the image in an "unbiased" fashion.