The science behind the arrest of Richard Bilodeau in the Theresa Fusco killing

Theresa Fusco, a 16-year-old girl from Lynbrook, was raped and killed in 1984. Three men were convicted of her murder, but were then exonerated after serving 17 years in prison when DNA found inside her body failed to match any of the defendants. Earlier this week, Nassau prosecutors indicted Richard Bilodeau, a 63-year-old Walmart employee from Center Moriches, with murder in Fusco’s killing based on what Nassau District Attorney Anne Donnelly said was a DNA match. Bilodeau was 23 years old, operating a mobile coffee truck and living in Lynbrook about a mile from Fusco’s home at the time of her murder.

How did prosecutors identify Bilodeau?

Bilodeau emerged as a potential suspect in Fusco’s murder last year. The FBI and Suffolk prosecutors had developed "multiple investigative leads" that Donnelly declined to detail after a Texas laboratory worked to create a DNA profile of the suspected killer and the FBI used genetic genealogy to find a suspect.

Nassau authorities began tailing Bilodeau, and last February, authorities retrieved a smoothie cup that Bilodeau had discarded at a cafe in Suffolk County, a so-called abandonment sample. FBI crime laboratory technicians were able to retrieve Bilodeau’s DNA from the straw and compare it to semen found in Fusco’s vagina during her autopsy. Nassau prosecutors said the samples matched.

The process was similar to what occurred in the case of alleged Gilgo Beach serial killer Rex A. Heuermann. Suffolk prosecutors said they initially linked Heuermann to some of the seven killings he’s charged with through saliva on a pizza crust he discarded in a midtown Manhattan trash can.

What is a DNA profile and how did the laboratory in this case determine a match?

Every human has a distinct DNA profile, much like a fingerprint. In 2023, Nassau County authorities submitted the forensic evidence from Fusco’s case — the unidentified genetic sample — to Othram Laboratory in The Woodlands, Texas. Scientists there developed a DNA profile from the evidence that was provided and then used a technique called Forensic-Grade Genome Sequencing, which analyzes degraded samples, to build a DNA profile for the unknown suspect, the laboratory said on its website. The profile was provided to the FBI’s forensic genetic genealogy team, which used forensic genetic genealogy to map out the family tree of the potential suspect, which authorities said lead to Bilodeau. The laboratory said on its website Bilodeau’s identification is the 16th case in New York that Othram has assisted law enforcement with its DNA technology.

How did advances in DNA technology over the decades help investigators in the Fusco case?

DNA evidence was not being used in U.S. Courts in 1986 when three men — Dennis Halstead, John Kogut and John Restivo — were convicted in Fusco’s murder. After the men were found guilty of killing the teenager, DNA testing performed on a vaginal swab taken from Fusco’s body was inconclusive in 1993, Newsday reported at the time. Testing in 2001 using newer methods ruled out the three defendants and indicated an unidentified perpetrator. The Innocence Project took on the defendants’ case based on the DNA results, leading to the guilty verdicts being set aside. The Nassau DA’s office retried Kogut, who had confessed to the crime but later recanted, but a Nassau judge acquitted him. The DA chose not to retry Halstead and Restivo.

Suffolk prosecutors used genetic genealogy, which involves comparing unknown genetic profiles to millions of others in publicly assessable databases, to identify Gilgo Beach victim Valerie Mack in 2020 — among the first times in New York State that law enforcement used the technique.

What is the hair banding evidence used in the original trial?

During the prosecutions of Halstead, Kogut and Restivo, authorities said they found two strands of Fusco’s hair inside of Restivo’s blue van, which authorities said the men were driving when they had picked up Fusco on the night she was killed. The defense argued that the hairs, which showed evidence of what is called "postmortem root banding," were planted inside the van by police. While forensic scientists have generally accepted that visible banding can occur on hair strands near the roots after death, according to the Department of Justice, experts disagree on whether it can be used to determine time of death.

By Nicole Fuller

nicole.fuller@newsday.com@NicoleFuller

Nicole Fuller is Newsday's senior criminal justice reporter. She began working at Newsday in 2012 and previously covered local government.