"According to the officers, it was a scene out of 'Friday the 13th,'" said Upper Darby Police Superintendent Michael Chitwood.
And it was a scene that developed after the suspect, Joshua Burno, reportedly called 911 shortly after 1:00 a.m. Monday, saying he was going to kill his mother, his brother, and then himself.
Chitwood says after the officers arrived at the home on the 2400 block of Greenhill Road, Burno's mother let them in, having no idea what they were talking about.
Moments later, Burno reportedly burst from a first floor closet swinging an axe at the officers, who fired two shots.
"This was an ambush, pure and simple," said Chitwood.
Investigators later found a box cutter tucked into Burno's pants and a large kitchen knife on the ground nearby.
The suspect suffered wounds to the ribs and left shoulder and remains in critical condition at the Hospital of the University of Pennsylvania.
Chitwood says Burno is expected to fully recover, although that is not what the suspect wanted.
"This kid wanted to die. He made the call, he lured the officers in so he could ambush them," said Chitwood.
Neighbors say they knew the young man was dealing with psychological issues, but they never dreamed it would come to this.
"They were nice people, I never had any trouble with them. They always waved to us when I saw them," said Bob Burns.
"Nice kids, both of them. Clean cut, always behaved themselves all the time growing up. It's just shocking that something like that would happen," said David Grant.
Assuming Burno fully recovers, police say he will face a long list of charges, including attempted homicide, aggravated assault and simple assault.