Ninhydrin Prints Developing?

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Ninhydrin Prints Developing?

Postby amydorsey » Mon Apr 23, 2012 6:15 am

Hello, I was wondering if an of you who do development have had instances where Ninhydrin development continued after the cases was considered to be complete? Have any of you recalled cases and seen instances where additional prints have developed? Thank you!
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Re: Ninhydrin Prints Developing?

Postby Pat » Mon Apr 23, 2012 7:22 am

The majority of prints developed with ninhydrin will appear per the schedule you are accustomed to, depending on temperature and humidity. However, some of those will fade in a matter of days, so photography as soon as the prints are clear is important. But as you are wondering, other prints will develop days, weeks, or even months later. Therefore, it may be necessary to rephotograph an item of evidence several times during the development/fading period in order to capture all of the latent images at their best. I'm no chemist, but I presume the variations in development and fading times are a result of differences in the specific amino acids and concentrations present in the latents.
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Re: Ninhydrin Prints Developing?

Postby amydorsey » Mon Apr 23, 2012 7:52 am

Thank you for your reply. Our laboratory is attempting to determine if there had been any examiners with personal knowledge of cases where Ninhydrin developed after they returned the paper case. Has this happened to you personally or do you know of any cases where that has definately occurred?
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Re: Ninhydrin Prints Developing?

Postby Pat » Mon Apr 23, 2012 4:49 pm

Amy,

To answer your question directly, yes. I cannot give you specific time delays because I cannot exactly date the development of latents on a document processed, placed in evidence, and checked out a year or two later that has additional prints that are not in the original photographs.

But your question begs some serious concerns. What was your department doing releasing the document back to the complainant after it had been processed? I see problems for several reasons, as follow:

1. The document is, by very definition, evidence. Once you release it back to the complainant, you have destroyed any evidentiary value by giving up any chain of evidence.

2. Unless you are using a ninhydrin clearing agent, active ninhydrin remains in the paper. Therefore, any additional handling with naked skin post-processing will probably result in additional latents. Those latents, of course, are not evidence of value for the original crime, but are conclusive proof of mishandling after the evidence was collected by the police.

3. The evidence should have been sealed in a clear plastic bag after processing and photography was concluded. Sealed and taped and initialed & dated across the tape or seal. Was that not done?

4. If the document was returned to the complainant and that person or somebody else handled it without gloves, their ridge skin would probably have turned purple where it contacted the paper. In addition, it would probably have developed the distinctive rotten smell associated with ninhydrin reaction on skin. If the person has a ninhydrin alergy (rare, but not unheard of), your department could be facing a lawsuit.

The more serious question is not whether latent print development can be delayed (just accept it as fact -- delayed development CAN occur). Instead, your department should be seriously examining its policies regarding release of evidence and exposure of complainants to chemical hazards.

Just my opinon.
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Re: Ninhydrin Prints Developing?

Postby Big Wullie » Mon Apr 23, 2012 9:56 pm

What colour would mixing ninhydrin and iodene produce ?

What colours are they seperately when applied ?
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Re: Ninhydrin Prints Developing?

Postby amydorsey » Tue Apr 24, 2012 9:50 am

Hey Pat,

The evidence is not being returned to the complainant and the evidence is being signed and sealed in plastic post analysis of the examiner. So chain of custody and sealing evidence is not in question. What is in question is accusing examiners of being incompentant due to the fact that paper cases have been recalled from storage and there are additional prints not previously recorded by the analyst at the time of examination. In my opinion, these prints developed AFTER the analyst was done with the case and the case was returned for storage. I feel Ninhydrin prints can continue to develop and I am meeting with opposition on this. I am on the side of the examiner and that the examiner is not incompentent and whatever prints the examiner recorded at the time of analysis was complete. Upon recalling the case some months/weeks later, it was determined that additional prints had developed and I am saying they did so after the examiner was done with case and that it was not examiner incompetency. But I agree with you. I dont feel Ninhydrin stops developing after the so called 24-48 hour rule. I just dont see how examiners can be labeled incompetent when the chemical can still produce prints "of value" months later. I thank you for your input, truly.
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Re: Ninhydrin Prints Developing?

Postby Pat » Tue Apr 24, 2012 10:12 am

Hi Amy

Police administrators often do not understand squat about what we do. I know one officer personally who had a formal reprimand for handling bloody evidence without gloves in violation of strict department policy. The officer swore she was wearing gloves, but was disciplined nonetheless. A year later when journal articles began appearing to the effect that latent prints could be left through latex gloves, that department changed its policy to require double gloving. Of course, they never rescinded the administrative action against the officer nor admitted the possibility that she was telling the truth when she said she had gloved up before handling the evidence. Instead, they threw that reprimand in her face a couple of years later when she was disciplined for another incident in which she was wrongly believed to have violated another policy.

You situation sounds analogous. Because stray prints develop in the nin some time after processing, they automatically think you or somebody else is lying, in spite of plenty of literature to the effect that prints DO develop late.

Best of luck to you,
Pat
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Re: Ninhydrin Prints Developing?

Postby Kathy Saviers » Tue Apr 24, 2012 10:25 am

I had a case just as you describe. It was years and years ago at a different agency, but I processed a notebook of drug sales. If I recall correctly, we were using ninhydrin in a petroleum ether solution at the time. For a while we used the Freon formula so I'm not positive.

I got prints on many of the pages. To document the position of the prints on the page, I copied each page on the copy machine and drew circles of the latent prints on the copies. I photographed and enlarged the identifiable latent prints. When done, I sealed up the notebook (we used paper bags or envelopes then) and returned it to the property room. I matched the suspects to some of the latent prints on different pages but not all of them. In those days, a couple of matches over different pages was adequate and we didn't spend (waste) our time comparing each and every fragment to the suspects but that's another topic.

About four or five months later, we were going to trial and I checked out the notebook. I compared the copies of the pages I made to the notebook and found that some latent prints got darker (clearer), some faded and new prints developed that didn't show up the first time. I believe I had the notebook for about a week the first time so I would have expected all of the prints possible to show up in that timeframe.

I suspect that all of us have seen ninhydrin prints fade over time. That was no surprise but I was surprised on the number of new prints that developed, though.

As to being called incompetent, that seems a shame to belittle employees for something they cannot control but that is the stick I've seen some accredited labs use to beat their employees.

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Re: Ninhydrin Prints Developing?

Postby amydorsey » Tue Apr 24, 2012 12:39 pm

Hey guys, thank you for all of your replies!! It does help as at least those of us in the fingerprint world are in agreement that not everything is analyst error especially when it comes to Ninhydrin. Its unfortunate that good people and some of us that have been in the field a long time, get a short stick. But getting this information and reaching out on this website has been great!! Best, Amy
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Re: Ninhydrin Prints Developing?

Postby Peter Griffin » Wed Apr 25, 2012 1:25 pm

At a lab where I used to work we would process an item with ninhydrin and record any latents, but we would wait at least another 24 hours before sealing it back up incase any other prints developed. I think it is documented in the literature that nin prints can develop well after first processing.

I would suggest if it is an issue your management has, rather than blame an examiner with something they cannot prove, just change their policy to (like Kathy did) photocopy or scan the pages for the case file. That way if someone notices prints down the road they can check to see if the examiner missed them based on the copies or scans.
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Re: Ninhydrin Prints Developing?

Postby Steve Everist » Thu Apr 26, 2012 7:50 am

During a break, before testifying in a paper case, I talked with the prosecutor about the evidence and what she was going to ask me to do regarding the prints, their location, etc... One thing she mentioned is that the paper had been put into sleeve protectors because of the chemical it was treated with. I didn't think much about that comment at the time. I usually try to keep a pair of gloves with me in case they ask me to handle evidence anyhow.

But once we went over the pages of paper, I realized why she had made the comment. I could see the marks I had made on the items when locating prints for photography. At this time, the ridge detail was faint. However there was a print that was better than most known exemplars we see, on the top page without any mark next to it. This surprised me at first, thinking how could I have missed such an obvious one, while the ones I had photographed were barely visible at this point. Then I realized that she probably made the earlier comment because someone had opened the evidence, ignoring the chemical warning stickers I had put on the packaging, and then realized what they'd done. I didn't happen to notice who had the purple thumb though.
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Re: Ninhydrin Prints Developing?

Postby Neville » Fri Apr 27, 2012 3:11 pm

Hi Guys
Well I am surprised that any expert out there does not know that ninhydrin continues to develop fingerprints and that fingerprints that have been developed may fade. It is one of the first warnings I tell o/c cases. Happens all the time though fading is less of a problem it can happen, usually a strong reacting fingerprint continues to develop until the detail almost becomes a purple blob.

I use to really annoy my boss as I always photographed the fingerprints when they developed as he saw it as a waste of time. But unlike some in my office I never got caught out when it came time for preparing a court case. I was once asked in court if I had identified the fingerprints on a piece of paper that were not labelled and photographed, they had appeared after I submitted the exhibits to court.

Amy you are correct your boss is wrong no doubts!

Big Wullie, Iodine is deep purple but fades to nothing in minutes, ninhydrin light to deep purple; when mixed, well it is just the ninhydrin colour as the Iodine will have faded before you get the paper into the ninhydrin.

regards
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Re: Ninhydrin Prints Developing?

Postby Big Wullie » Sat Apr 28, 2012 8:59 pm

Thanks Neville

If you came across a bloody fingerprint what would you do first ?

If you came across a bloody fingerprint would you ever apply Ninhydrin and Iodine or would this possibly destroy any traces of blood ?

How would you preserve any evidence of the bloody print ?

Can anyone tell me what colour would be produced mixing Ninhydrin with Iodine on a print ?

Neville am I to take it from your comment then that the Iodine would be applied to the paper then the paper would be placed in Ninhydrin ?

If we were to talk about a print on a wall being enhanced with Ninhydrin and Iodine how could this be achieved ?

Thanks in anticipation
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Re: Ninhydrin Prints Developing?

Postby Steve Everist » Sat Apr 28, 2012 9:06 pm

Big Wullie,

If you're interested in processing methods and sequencing, there's a lot of information here: http://www.cbdiai.org/Reagents/main.html
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Re: Ninhydrin Prints Developing?

Postby Neville » Sat Apr 28, 2012 10:13 pm

Hi Big Wullie
Sounds to me like you have a situation in mind, a case. It really depends on so many things and if you are talking about an old case the way things are done now maybe different to 15yrs ago, in the UK as I remember it (depending on where you lived) Idodine spraying was common place and was used first but as I said, to many factors to say as each case is different. The colour of the wall paper would dictate what you use as would the seriousness of the offence. I would use the Polilight first as it is non destructive.
20yrs ago DNA was not such a big deal and in NZ we tended to use amino black over most things. Here if you mention spraying Iodine the OSH people go into orbit, as they say times are a changing.

Unfortunately you are asking to many different questions in one go to answer and you are probably venturing way outside this topic.
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