Crime How a Business Student's Dying Cries of 'Help Me' Eventually Led to a Serial Rapist The 1998 rape and strangulation murder of Shannon Schieber went unsolved for more than three years By Chris Harris Chris Harris Twitter Chris Harris has been a senior true crime reporter for PEOPLE since late 2015. An award-winning journalist who has worked for Rolling Stone and MTV News, Chris enjoys prog rock, cycling, Marvel movies, IPAs, and roller coasters. People Editorial Guidelines Published on November 12, 2018 01:12PM EST Share Tweet Pin Email Two decades ago, the brutal rape and murder of a 23-year-old business student shocked Philadelphia. On the afternoon of May 7, 1998, the nude and strangled body of Shannon Schieber, a popular doctoral student at the University of Pennsylvania’s Wharton School, was discovered inside her Center City apartment. Investigators announced soon after that they were pursuing a serial rapist, and fear spread throughout the city. For three years, Schieber’s killer continued to rape, eventually moving to Fort Collins, Colorado, where he targeted college-aged women. Troy Graves, 46, was apprehended in 2001, and, after pleading guilty to his crimes in Colorado and Pennsylvania, he was eventually sentenced to life in prison. Schieber’s tragic murder and the pursuit of the man dubbed by police as the “Center City Rapist” is featured on People Magazine Investigates on Investigation Discovery. Titled “Terror in Philadelphia,” the episode airs on ID tonight at 10 p.m. ET. An exclusive clip about the investigation is shown above. • For more on this story, watch “Terror in Philadelphia,” the latest episode of People Magazine Investigates, airing tonight at 10 p.m. ET on Investigation Discovery. Police were heavily scrutinized for their initial handling of a call to Schieber’s apartment. A neighbor, Parmatha Greeley, called 911 after being awakened by screams of “Help me! Help me!” Greeley ran to Schieber’s apartment, pounded on the door and shouted that he was calling police. “I just heard like a choking sound,” he told the 911 operator. Courtesy Schieber Family • Want to keep up with the latest crime coverage? Click here to get breaking crime news, ongoing trial coverage and details of intriguing unsolved cases in the True Crime Newsletter. Within seven minutes, two policemen were at Schieber’s door, but they left after they knocked on the door and got no answer. “The hardest thing to accept, is that our daughter did everything she could to call for help,” Syl Schieber, Schieber’s now 72-year-old father, told PEOPLE in 1999, soon after filing an unsuccessful lawsuit against the city and its police. “Think if it was your daughter calling out for help and the police just walked away.” People Magazine Investigates: Terror in Philadelphia airs tonight at 10 p.m. ET on Investigation Discovery.