On the evening of December 29, 1986, California Highway Patrol Officer Craig Py was driving his cruiser down Interstate 15 in San Diego, California. With him were an NBC news reporter in the back seat and a cameraman in the passenger seat. They were filming a segment about highway travel safety, scheduled to air on the Evening News later that night.
Officer Py followed his typical patrol route, but as they passed a sign for the Mercy Road exit, he turned to the news team and pointed. “That’s where they found the body,” he said.
A Murder on Mercy Road
Just over 36 hours earlier, at around 4:00 a.m. on December 27, 1986, a 20-year-old college student named Cara Knott had been found strangled to death in a creek near the Mercy Road exit. Cara had been on her way home from her boyfriend’s house when, for unknown reasons—perhaps car trouble or an attempt to help someone—she ended up in that cul-de-sac. There, she encountered someone dangerous who took her life.
The killer had not yet been caught, which was why the California Highway Patrol and NBC News were collaborating on the segment. The goal was to educate drivers on how to stay safe if they ever had to stop along the highway.
The Filming of the Safety Video
As Officer Py continued down Interstate 15, he discussed highway travel safety with the news crew. He warned about the dangers of stopping on the highway, emphasizing that once a person leaves their vehicle, they become vulnerable. “Being a female, you could be raped or robbed. If you’re a male, you could be killed,” he stated. He also cautioned against getting into a stranger’s car, noting a running theory that Cara may have entered her killer’s vehicle.
During the segment, Officer Py noticed a car pulled over on the shoulder with its hazard lights on. He saw this as an opportunity to demonstrate real-time highway safety tips. Pulling his cruiser behind the stalled vehicle, he stepped out and gestured for the news crew to follow.
Officer Py approached the car’s passenger-side window and asked the driver to step out. The man explained that he had run out of gas, walked to a gas station for fuel, and returned, but his car still wouldn’t start. Py pointed out on camera that leaving one’s vehicle and walking along the highway was extremely dangerous. The driver shrugged off the warning. Officer Py then called for a tow truck, and after assisting the stranded motorist, he and the news crew continued filming.
The Video That Solved a Murder
Later that night, Officer Py watched the segment as it aired on NBC. To him and the California Highway Patrol, the minute-and-a-half clip had gone well—it covered the key safety points and showed him helping a stranded driver. He thought nothing more of it.
However, within an hour of the broadcast, police lines were flooded with calls. Viewers had noticed something shocking in the segment, and they were certain they knew who had killed Cara Knott.
The Break in the Case
Police followed up on the tips, and within two weeks, they had enough evidence to arrest Cara’s murderer. The crucial clues had been hiding in plain sight within the broadcast.
It turned out that the same person who had murdered Cara had terrorized over two dozen women in San Diego. These women had survived their encounters, but they had been held hostage, threatened, and attacked before being released. When they watched the segment, they immediately recognized the man featured in the video—he was their attacker.
On the night of Cara’s murder, she had pulled off Interstate 15 at Mercy Road and stopped in the cul-de-sac. What happened next mirrored the experiences of the other women—except Cara never made it out alive. During their encounter, the killer struck her over the head and strangled her to death with a rope. He had gotten away with the crime—until he appeared on television.
As the segment aired, the women who had survived noticed something else: the man on the screen had a fresh cut over his eyebrow. They realized this was the person who had attacked them, and now, they were sure he was also Cara’s murderer.
The Shocking Identity of the Killer
Police confirmed that the man in the news segment, the one with the fresh cut over his eye, was indeed Cara’s killer. That man was none other than Officer Craig Py.
Py was arrested, found guilty of murder, and sentenced to 25 years to life in prison. Since his incarceration, he has been denied parole twice. He is scheduled for another parole hearing in 2027.
What began as a routine safety video ended up solving a murder case. Thanks to the sharp eyes of survivors and the power of television, justice was served for Cara Knott.