The victim's brother says an encounter with her a week before her death has always troubled him.
LANGHORNE, Pennsylvania (WPVI) -- Nearly five decades have passed since the fatal stabbing of a teenage girl in the parking lot of a Bucks County mall.
Now, her brother is coming forward to make a plea to finally close her case.
Glen Bartlett was 13 years old when his sister Patty Bartlett was killed.
"Feels like yesterday," Glen recalled.
He says Patty's passion was photography.
"She was going to the Philadelphia Art Institute for photography."
On January 13, 1975, 17-year-old Patty was out getting film.
"The first snowfall of the season, she was going to get film up at the Oxford Valley Mall," Glen said.
At 5:30 p.m., Patty was walking to her car when she was attacked. Police say she was stabbed four times.
She made it back into the entrance of the store Gimbel's to get help. That's when medics rushed her to the hospital, where she later died.
Police say robbery being the motive in this case is unlikely since her purse, wallet, and shopping bag of photo supplies were all recovered at the scene.
Glen says an encounter with Patty a week before her death has always troubled him.
"I remember her working. She was working as a waitress at Coco's and somebody followed her home. She was scared to death of the guy," he said. "After about five minutes the guy took off, he left and a week later she was gone."
The Citizens Crime Commission is administering a $5,000 reward for information that leads to the arrest and conviction of the person responsible.
All you have to do is call 215-546-TIPS. All calls will remain anonymous.