I had a new DNA detective case last week. I connected via Reddit with a young woman in Las Vegas, who I’ll call Maria. She had done the 23andMe test, and was surprised to find that her ancestry was more or less exactly 25% African. Her mother’s family are of European descent, and her mother had always told Maria that her father was Mexican or Central American, but also that she could not remember any more details. (Her mother is, to put it delicately, not a reliable reporter. Maria and her half-brothers have been brought up by their mother’s parents.)

By the time I connected with her, Maria had already put most of the pieces together herself, and in particular had found someone on 23andMe whose DNA overlap with her is 16%, within the range that you’d expect for a first cousin (or a half-aunt/uncle or half-niece/nephew, or a great-aunt/uncle or great-niece/nephew or a great-grandparent, but we can eliminate those possibilities for various reasons). The cousin recalled a long-lost uncle, Jamie Jr, named after her equally long-lost grandfather, Jamie Sr. The cousin also provided a recent photo of Jamie Jr and Rose, his mother, and Maria and her other grandmother felt confident that there was a resemblance between her and Jamie Jr around the nose and eye shapes. Rose is of European descent, and Jamie Sr is African-American, so that tied up neatly with Maria’s genetic results.

It took a couple of days for Maria and me to untangle the various possibilities, including dead ends and false trails in Louisiana and Pennsylvania. I was eventually able to track down both Jamie Sr in Portland, Oregon, and Jamie Jr in Los Angeles. To make matters more complex, both are known by their (shared) middle name, which has an unusual spelling that the cousin did not know about. Putting together the DNA tests, family history and public records, Jamie Jr is almost certainly Maria’s biological father, unless he has a brother somewhere who has been forgotten both by his family and by California bureaucracy.

I found no record of Jamie Jr having married or having had other children, but the closer you get to the present day, the less reliable it is to argue that absence of evidence is evidence of absence. However, he has a substantial criminal record, which is partly why it was relatively easy to find a trail for him online. Maria is familiar with her mother’s taste in men, and was not surprised by this at all. Given her mother’s general vagueness (to put it delicately again), Jamie Jr is almost certainly unaware of Maria’s existence.

Maria has decided to keep it that way. She has a name and a photo, and an explanation of why she looks quite so different from her half-brothers. But, as she put it in one of her emails, “I don’t need another disappointment and false hope in my life after what my mother has put me through. I think having my answer is satisfying enough .” She is still at high school, but she has a good head on her shoulders.