Blog 2: The Technical Aspect of Genetic Geneaology

The second of Arianna Jeanbaptise’s blogs regarding the use of genealogy in the Bear Brook case for her senior project.

Blog 2: The Technical Aspect of Genetic Geneaology

As I am beginning to learn more and more about genetic genealogy, I’m realizing that there are many technical aspects to it. It’s really not that simple actually. 

In cases where a suspect has been identified, investigators can require him or her to take a simple DNA test in order to gather the genetic material. According to, samples can include hair, teeth, fingernails and skin. In cases where they don’t have a suspect, investigators collect DNA evidence from the scene and use the same process. 

With DNA testing, criminal investigators and genealogists can get some basic information about a person. For instance, The Guardian explains that genetic testing can reveal eye and hair color, and gender. It can also provide clues about which regions of the world people’s ancestors might have come from, according to Medline Plus

With the Bear Brook case, investigators had to extract DNA from a strand of hair that no longer has the DNA rich-root attached. It was difficult to identify the victims in the case, but the hair was preserved which made the identification process a bit easier. That would be needed in order to conduct DNA testing. Without it, no tests can be done because there will be no evidence to test DNA from.

Once the testing is completed that information from the testing gets put into a database providing more advanced information. The database combines new information with existing information to provide more clues. When trying to identify individuals associated with the case, law enforcement enters DNA evidence into the CODIS database. According to, CODIS stands for a Combined DNA Index System. It is a national database that has multiple indexes that contain DNA profiles of convicted offenders, profiles for missing people, as well as profiles for unsolved cases. CODIS is indeed an important tool for investigators because it was designed to compare a person’s DNA to a DNA test that may already be in the CODIS database. Once a match is made, laboratories verify the matches to ensure they are the proper person for the match.

Not only are government databases being used to identify suspects, but commercial genealogical databases are used by genealogists to provide more advanced information that links clues. According, VNEWS, the genealogist that worked with the case, Barbara Rae-Venter, uses genetic profiles along with an “open-data personal-genomics database and genealogy website” to create family trees. She also uses birth records, newspaper clippings, social media profiles and family tree data to create those connections. The reason these genealogic databases are being used is because amateur genealogists got involved in trying to solve the Bear Brook case.

For example, with the Bear Brook case, Rae-Venter was able to help identify Terry Rasmussen as the killer because of her work with genetic genealogy. Rasmussen went by multiple names, which is why he was also known as the “ chameleon killer”. According to WMUR, the names that he has used in the past were Robert “Bob” Evans, Curtis Mayo Kimball, Larry Vanner, Gordon Jenson and Gerry Mockerman. Investigators and genealogists, therefore, relied on DNA testing and the use of genetic genealogy to help find clues to solving the case.


I did not know that forensic genetic genealogy was as complicated as it is, but I was able to get a better understanding of it and how it is used not only in the Bear Brook case, but in many other cases in the U.S today. 

As I was speaking to Sergeant Matthew Koehler, he informed me that so far since the Bear Brook case, he has not worked on any cases using this new technology, but he is sure that in the future he definitely will. Over the past years, genetic genealogy has grown tremendously. The process of finding people has become faster and efficient.  Koehler explained that there’s always room for improvement. For example, with a stand of hair, there would need to be a bulb, which is the base of the hair root shaped somewhat like a ball. 

 As science improves, we need less equipment and materials to conduct tests. In the future, there might be a smaller amount of samples needed to take DNA testing. Another way to improve genetic genealogy is to  build a greater database for DNA testing to get matches to victims quickly. A challenge that many genealogists and cold case units face today is not having the proper databases.This is important because without it, investigators would not be able to identify people.

Thank you for reading! In my last and final blog, I will be discussing how long it takes to find people, specifically the killer and the victims using genetic genealogy. Stay tuned!

This blog is part of my Senior Project for Souhegan High School, which I conducted over the last two months. I was able to learn a lot of new information about forensic genetic genealogy and I am glad to be able to share it with all of you! I’d love to hear your thoughts on my project. Contact me!