But investigators never received a match through Codis.
Dan Krane, a professor of biology at Wright State University in Dayton, Ohio, who has researched tools to evaluate DNA evidence for criminal investigations, said by phone on Tuesday that in 1997, “Codis was still very young,” with only about two million people in the database, compared with roughly 14 million today.
Most of the DNA in the database comes from criminal offenders or people who have been arrested and had their DNA collected, Professor Krane said.
In December 2020, Cece Moore, a genetic genealogist who works with Parabon NanoLabs, a Virginia company whose services include novel DNA-based forensics, was given a DNA sample from the crime scene by the authorities.
The DNA tests from the person showed that he had many recent immigrant family members from Italy.
Ms. Moore found that there were about 2,300 residents of Italian ancestry living in the area at the time of Ms. Biechler’s death. From there, she further narrowed the pool of potential suspects to those whose ancestors had lived in Gasperina, Italy.
Then, using newspaper archives, public search databases, social media, court records and other resources, Ms. Moore determined that Mr. Sinopoli, who has Italian ancestry, was a possible suspect, in part because he had lived in the same apartment building that Ms. Biechler had. She said at the news conference that she had later submitted a “highly scientific tip” to the authorities.
Investigators surveilled Mr. Sinopoli, eventually following him into the airport. There, they retrieved a coffee cup that he had discarded.