The South Side Strangler:Timothy Wilson Spencer·Debbie Davis·Susan Hellams·Diane Cho·Susan Tucker

Between September and November 1987, a killer broke into homes in Virginia and strangled four women. Debbie Davis, 35, and Dr. Susan Hellams, 32, a neurosurgery resident, were killed in Richmond’s Southside. Fifteen-year-old Diane Cho was murdered in Chesterfield County on November 22, and within days Susan Tucker, 44, was found dead in her Arlington home.

Arlington detective Joe Horgas noticed that the Tucker killing closely resembled the 1984 murder of Carolyn Hamm in the same county. A man named David Vasquez was already in prison for that crime. Horgas doubted he had acted alone, and his investigation turned to Timothy Wilson Spencer. Genetic testing, then brand new in American courts, linked Spencer to evidence from the killings, with the chance of a random match put at one in 705 million.

In July 1988 an Arlington jury convicted Spencer of murdering Susan Tucker, one of the first murder convictions in the United States built on DNA evidence, and later trials added convictions for the deaths of Debbie Davis, Susan Hellams and Diane Cho. DNA also cleared Vasquez, who received an unconditional pardon in January 1989 after about five years in prison. Spencer was never tried for Hamm’s death. He was executed in Virginia’s electric chair on April 27, 1994, the first person in the country put to death in a case resting on DNA evidence.