Investigative Genetic Genealogy

A new tool available to prosecutors and detectives to resolve violent crime and unidentified human remains cases when traditional techniques have been exhausted. I've successfully identified several unknown persons using this methodology.


IGG provides workable leads for law enforcement using DNA databases with testers who have agreed to assist them. The genealogy itself is not considered evidence and the genealogist doesn’t need to provide testimony. Existing protocols are followed in order to obtain suspect samples once the candidates have been identified.

IGG can used in both active and cold violent crime cases as well as identifying unknown human remains. It has resulted in numerous successful prosecutions.

Some successfully prosecuted IGG cases include:

Golden State Killer

Phoenix Canal murders

William Earl Talbott

More cases can be found on the ISOGG website.

The Benefits

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Before IGG begins, an STR profile should have already been submitted to local, state, and national CODIS databases with no hits.

  1. SNP profile is created with available DNA

  2. Profile is uploaded into approved databases

  3. DNA matches are identified

  4. Family trees are constructed upward until “Most Recent Common Ancestor” is found

  5. Family trees are constructed downward and possible candidates are identified

  6. Additional target tests may be conducted to prove hypothesis

  7. Law enforcement decides when a suspect DNA sample should be obtained

The Process

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IGG is most likely to work for Americans of European descent, though the number of testers of other ethnic backgrounds is growing. Every family is unique so every case will be unique too. IGG can be time-consuming with no guarantee of a result. DNA samples that are contaminated or damaged may produce a skewed DNA profile or none at all. Additionally, detectives should be prepared to reach out to family members asking for voluntary samples. Thankfully, history has shown that people are generally willing to assist law enforcement.

Information about many of the legal and technical aspects of IGG can be found on the ISOGG website.

Some Cautions