The 22-year-old cold case trial against Joseph Martinez, aka "Jupiter Joe," unfolded continued in court for a second day on Monday.

The case was the first New York City investigation using familial DNA technology to come to trial.

Martinez is accused of strangling and discarding the body of 13-year-old Minerliz Soriano’s in a dumpster back in 1999.

The trial’s third witness took the stand Monday - a DNA expert who worked at the Office of the Chief Medical Examiner in 1999.

The expert confirmed that the stain found on Soriano’s sweater, which contained DNA matching Martinez, was semen.

This testimony follows the defense’s claims from the first day of trial, where Martinez’s attorney suggested that the stains could have been caused by mucus or particles from riding an elevator during flu season, rather than being evidence of a crime.