Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

A team of Philadelphia real estate investors said a house they purchased was booby-trapped with a swinging knife that could have killed someone.

Ekrem Uysaler said he was among five people last month walking through a home purchased in the Angora neighborhood of southwest Philadelphia when they made the scary discovery.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

Uysaler's ABC Capital Investments buys distressed properties, renovates and sells them to investors. So he's accustomed to odd discoveries.

A house in southwest Philadelphia was booby trapped with a knife - attached to an upside-down crutch - rigged to swing down to the face level of an unsuspecting victim. Courtesy Ekram Uysaler

"I come across this every day — abandoned dogs, homeless people squatting, drug houses with bags and scales — but never a trap," Uysaler told NBC News on Friday.

He took cellphone video of the terrifying scene.

A staircase inside the three-bedroom home was rigged with a line of string, running parallel and about 4 inches high over one step, he said. If anyone had tripped that string, it would have triggered a crutch with a knife attached to it to fall from above.

"Whoever did this was a genius, like Stewie," Uysaler said, referring to the violence-obsessed character on the popular TV cartoon "Family Guy."

"If you lift your foot you would have caught that line, and the knife would have come swinging down to your throat or face."

Despite the shocking discovery, Uysaler said the company is still going forward with renovations on the house — which had been abandoned for at least three years — that should take another four months.