Police in O’Fallon, Missouri say a 57-year-old woman was forced to shoot a male assailant after he chased her into her home on Little Brave Drive shortly after noon last Tuesday.

“This initially began in her driveway, she was in her car, the person, the deceased, approached her there and then there was some type of confrontation. She ran in to the house and he followed her,” said O’Fallon Police Chief Roy Joachimstaler.

The woman, identified by authorities as Pamela Hupp, told police she had been sitting in her car in the driveway of her home when the man approached her. After a swift altercation, the woman became fearful and ran from her car into the house.

Hupp then called police to report a burglary in progress around 12:10 p.m. but the man reached her inside her home before police arrived on scene. Authorities said Hupp, who had secured a firearm at some point, fired several shots, killing her assailant. She then called the police back to report the shooting.

When officers arrived, they discovered the body of 33-year-old Louis Gumpenberger in the woman’s home.

A woman claiming to know Gumpenberger said he had suffered a traumatic brain injury in a car accident and said he could be easy-going, then violent at times.

Authorities said they do not believe Hupp and Gumpenberger knew each other and police say the investigation is ongoing at this time.