Five things I learned at the Forensics Tutorial

fingerprint analysis lab

Participants got to try their hand at doing a fingerprint analysis.

I don’t know about you, but I am fascinated by forensics. Crime scenes are puzzles waiting for someone to solve. So, I, along with some other staff members, sat in on part of the Forensics tutorial held in August.

Here are five things I learned while I listened in on the tutorial:

1)Unlike “CSI” or whatever your favorite cop show might be (mine is “Dexter”), the methods used at the crime scene are not nearly as scientific as you would expect. That’s where statisticians and applied mathematicians come in. There is a plethora of areas where adding statistical or mathematical methodologies to the field of forensics can make a tremendous impact in helping law enforcement catch the right people.

2)A lot of forensic evidence comes from inductive inferential processes, which is not a very good/reproducible way to gather evidence. Bill Tobin, from Forensic Engineering International, told us that they do not share error rates and there is no “peer review” for the evidence.See one of his presentations here.

3)There are many factors that are often overlooked or are not explored in firearm toolmark evidence (Firearm toolmarks are used to associate or eliminate a particular firearm as a murder weapon comparing characteristics imported to bullets and cartridge cases when it cycles through a gun.) but there are ways that forensic experts could use a more scientific approach to make this a more credible piece of evidence. See Cliff Spiegelman’s talk for more information about this.

Andy Parker dusting for fingerprints

Andy Parker shows the group how he dusts for footprints.

4)Andy Parker from the Wake County Crime Bureau Investigation team is awesome! He talked about what his job entailed and showed us several slides (sorry, they cannot be shared) of dead bodies and had us guess if it was a murder, suicide or death by accident. Then he explained how one could conclude which was correct. Later, he had us all gather around and showed us how they dust for prints, including footprints. It was really neat!

Herbert David Sheets

Herbert David Sheets, Canisius College and University at Buffalo, talks about bitemarks.

5)The uniqueness of bite marks is not been scientifically established, and the uniqueness of a bite mark to make a unique pattern in someone’s skin has also not been scientifically established. See Herbert David Sheets’ presentation for more info.

Overall, this is a fascinating topic that applied mathematicians and statisticians have traditionally not been involved with, but that needs your attention. Saving an innocent person from being in prison and/or catching a criminal who may still be free is vital to keeping our society whole. You can still get involved by attending one of SAMSI’s subsequent workshops which will be posted on the SAMSI website sometime in the near future.

Why you should attend the SAMSI Forensics 2015-2016 opening workshop

The following was written by Dr. Clifford Spiegelman, Distinguished Professor of Statistics at Texas A&M and one of the program leaders for the 2015-2016 SAMSI Program on Statistics and Applied Mathematics of Forensic Science.

Cliff Spiegelman

Dr. Clifford Spiegelman

Imagine having a nightmare where nearly all evidence presented in courts was seriously misrepresented. No, not a nightmare about someone accused of being a witch, but a more current trial. Say the defendant is accused of rape or murder and all the scientific evidence presented was seriously misrepresented and biased toward the prosecution. It would not be a pleasant dream, but it is today’s reality, and that is worse than a nightmare as it is real. Within the last months the FBI has admitted to over representing the importance of hair matches for decades. Prior to that in 2007 CBLA or comparative bullet lead analysis was another procedure used for decades where the FBI admitted to overstating the importance of a match.

Forensic science is inherently a field that uses data (patterns, pictures, etc.) to link suspects to crimes. Unfortunately, the use of formal statistical methods or even statistical or mathematical thinking is uncommon.

That is where you can help. There is a dearth of persons, as in way to few mathematical scientists, that are aware of the issues.

What are the issues?

Well one can read the summary of the 2009 NRC report “Strengthening Forensic Science in the United States: A Path Forward” to get a good overall view. Here are some of my recent consults: A defendant was charged with indecent contact with a minor. The minor had chlamydia but the defendant did not and was not treated for chlamydia. What is the probability? In another case a convict has been in jail for 40 years largely based upon hair and fiber evidence. The hair evidence was inconclusive. That is the crime lab hair examiner testified that there were both similarities and dissimilarities between the pubic hairs found at the scene and on the defendant. Subsequently some inconclusive results (not the case in question as the evidence has gone missing) have been investigated using DNA. What are the odds that an inconclusive microscopic hair analysis has a DNA analysis that excludes the defendant? It is more than ½.

The opening workshop will look at various forms of traditional pattern evidence. These include fingerprints, firearm/toolmarks, shoeprints etc.. Help become part of the birth of taking forensic science from oxymoron state to a real science.

The opening workshop program can be found here. Read more about the overall program here, and if you want to learn more about forensics before the opening workshop, consider attending a special tutorial a few days before the big event begins.

Please join us. You can make a difference to the legal system and make our country a more just place.