A New Jersey judge ruled that prosecutors can use evidence from a powerful and increasingly common DNA tool in the upcoming trial of a man charged in the 2018 murder of four relatives.
Monmouth County Judge Marc Lemieux agreed with prosecutors that STRmix, which allows forensic analysts to test tiny, complex DNA samples that likely would have been considered unusable a decade ago, had withstood repeated testing and been found reliable.
“STRmix works, and it appears to work very well,” he wrote in a 212-page ruling last week.
Defense lawyers for Paul Caneiro, who is awaiting trial in the murder of his brother and his brother’s family, had urged the judge during a weekslong hearing last year to block evidence gathered using STRmix because they said it had not been properly vetted for use in criminal cases.
Caneiro, who was 51 at the time of the killings, has pleaded not guilty to charges of first-degree murder in the slaying of Keith Caneiro, 50; Jennifer Caneiro, 45; and their two children, Jesse, 11, and Sophia, 8.
They were found in their home on Nov. 20, 2018, in Colts Neck, 47 miles south of New York City.
Prosecutors have alleged that Caneiro fatally shot his brother, stabbed his niece and nephew, and shot and stabbed his sister-in-law before he set their home ablaze. He then set his own house on fire in an effort to cover up the crime, authorities have alleged.
Jury selection is expected to start in May.
Prosecutors introduced more than a dozen DNA samples in the case using STRmix, which was developed by scientists in New Zealand and Australia and introduced in the United States roughly a decade ago.
Experts have said the software — which uses statistical modeling to analyze complex samples obtained from something as small as a few cells left on a doorknob — has revolutionized how DNA is analyzed and is now likely used by a majority of forensic labs in the United States.
In one instance in the Caneiro case, DNA analysts were unable to obtain results using traditional methods when analyzing a pair of bloodstained jeans discovered in Paul Caneiro’s basement.
But after the lab started using STRmix, the software showed that DNA from the stain was 2.7 septillion times more likely to have come from Paul Caneiro’s nephew than someone else, a forensic analyst said during the hearing.
Paul Caneiro’s defense lawyers had challenged the software, saying it hadn’t been proved reliable in the same way that “safety-critical” systems used in cars and airplanes are. STRmix, they said in a brief, can produce false results that could help wrongfully convict someone.
