In 2004, two young women were abducted at gunpoint while walking home near Boston at night. The crimes happened eight days apart, but the pattern was the same: The women were shoved into a car by two men, pistol-whipped, driven to a different location, and raped. While collecting her clothes, the second victim managed to grab the condom one of the men had worn; she hid it in her pocket, and turned it in as evidence.

One of the two men involved pleaded guilty to the attacks in 2012. The other remained at large. Police had a suspect, but they couldn't pin the crime on him due to a twist of genetic fate: He had an identical twin brother, and DNA from the condom matched both siblings. But now, a decade after the assaults, scientists have developed a genetic test that can distinguish between identical twins, and it may be used in court for the first time in this case.

The second suspect is 33-year-old Dwayne McNair. In September, McNair was arraigned on eight counts of aggravated rape and two counts of armed robbery, stemming from the two sexual assaults.