JonBenet Ramsey was six years old. She was a little girl in beauty pageants, and she was murdered in Boulder, Colorado, the day after Christmas in 1996. Nearly thirty years later, no one has been convicted. The file is enormous. The answers may already be in it.

What is new is the tools. In 2008, touch DNA on her clothing was matched to an unknown male, and not to anyone in the Ramsey family. The sample is small, and some of it is mixed, so the police have been careful. A test can use up the only material they have. Boulder’s police chief has said the department is talking with labs about forensic genetic genealogy, and that they may get only one shot.

That kind of testing is how other cold cases have been solved. A lab reads the DNA down to the small markers called SNPs. Those markers can be compared with people who have put their own DNA into genealogy databases. A match does not have to be the killer. It can be a distant cousin. From there, investigators build the family tree backward until one person fits the time, the place, and the evidence. Her father, John Ramsey, has said the killer’s DNA is already in hand, and that this is the tool that could put a name on it. He has also said an outside researcher offered to run that genealogy with an artificial intelligence program, at no charge, if the police will turn over the data.

The paper record is the other half. The ransom note, the interviews, the tips, and the old reports are more than any one person can hold in their head and compare. A powerful system can read that pile, line up dates, and set one statement next to another the way a team of readers would, only faster and without forgetting page 400. Handwriting, names, and times can be checked against each other in one pass.

None of that is a verdict. It is a reason the case is not stuck where it was in 1996. DNA that can reach back to a cousin, and a machine that can read the whole file, give this murder a new hope of being solved.