Law & Order: Special Victims Unit: Season 2, Episode 15

2 - 15: Countdown

The detectives work around the clock to find an abducted girl when clues point to a serial killer who kills his victims after three days, and follows a very specific pattern: during the three days the man has a Party Day, a Picture Day, and finally a Special Day on which the victims are raped and murdered. The investigation is assisted by the killer's last victim, who escaped.