Colleen Fitzpatrick

Colleen Fitzpatrick is a forensic genealogist whose consultation with Michelle McNamara brought the methods and limits of genetic genealogy into the search for the Golden State Killer. Her contribution was not a confirmed identification: the available comparisons offered no clear family line to follow, but suggested a way to reason from distant matches and recurring patterns in names.

Background and Expertise

Fitzpatrick helps people find their birth parents and had also contributed to solving major crimes, including Phoenix’s Canal Killer case. She wrote a book on forensic genealogy and spent many hours discussing with McNamara how genealogy might help identify the Golden State Killer. Their conversations extended into the early morning, reflecting the sustained, practical nature of the consultation rather than a single exchange of ideas.

Method and the Limits of the Evidence

After McNamara’s death, Fitzpatrick explained the results to Billy Jensen. Distant Y-DNA matches can be informative when the people who match share a surname: that repetition may point to the suspect’s last name and to an extended family connected through the direct line, potentially reaching back many generations. A set of varied surnames, by contrast, does not support pinning down one family name.

Fitzpatrick also described how the general character of surnames might suggest an ancestry, even when it cannot establish an identity. If a list of matches contains names associated with one background, that pattern may offer a tentative ethnic clue. In the Golden State Killer work, the names had a German quality but suggested a person from the United Kingdom. Fitzpatrick presented that as a flavor in the results, not as a verified origin or a conclusive lead.

The Canal Killer Example and Her Contribution

Fitzpatrick drew on her earlier work on Phoenix’s Canal Killer to explain why such a pattern could matter. In that investigation, she identified Miller as a likely surname and told the Phoenix Police Department that the person was probably a Miller of Irish extraction. A few weeks later, authorities arrested Bryan Patrick Miller. The example gave a concrete basis for considering surname and ancestry patterns, while not making the same inference about the Golden State Killer conclusive.

Her role in McNamara’s investigation therefore lay in interpreting what the genetic comparisons could and could not support. The variety of names prevented a usable lineage from emerging, but did not make the data empty: Fitzpatrick treated its recurring qualities as a clue worth considering, while preserving the distinction between a suggestive pattern and an established identity.