KEY LARGO (CBSMiami) – A teenager accused of killing his brother and stabbing his father Thursday morning is fighting for his life after jumping in front of a moving vehicle.

The tri-county search for 17-year-old Daniel Weisberger came to an end not far from the murder scene.

“I stop my truck, started directing traffic behind me,” said witness John Jankowski.

Jankowski was just driving down U.S. 1 near Founders Park when he says it “absolutely” looked intentional when someone jumped in front of a moving car.

“I seen the man run out from that side of the road across the southbound lane into northbound lane, and ran right into the side of the truck is what it appeared to me,” he said.

The person who was hit was confirmed by the Monroe County Sheriff’s Office to be Weisberger.

He remains at Jackson Memorial Hospital where his condition is described as severe.

Weisberger is accused of stabbing and killing his 14-year-old brother and seriously injuring his father, Ariel Poholek, at the Executive Bay Club townhomes near Mile Marker 87.2 in Islamorada.

When Monroe County Sheriff’s deputies arrived, Weisberger was gone.

Poholek was airlifted by Trauma Star to Ryder Trauma Center in Miami.

It’s unclear what spurred Weisberger to stab his younger brother and then his father, said sheriff’s spokesman Adam Linhardt in an email.

Linhardt said a number of agencies, including Miami-Dade police, assisted in the search for Weisberger, who was consider armed and dangerous.

After being located, Weisberger was taken to a Miami hospital with serious injuries.

Monroe County Sheriff Rick Ramsay called the fatal stabbing a “heinous crime,” which was discovered when a neighbor called 911 after a bloody Poholek came to his door, bleeding saying his own son stabbed him.

Poholek reportedly told the neighbor that Weisberger stabbed his younger brother multiple times, including in the neck.

Poholek worked for NOAA Fisheries, who released the following statement:

“We are deeply saddened by this unexpected tragedy. Our thoughts are with Ariel and his family, and we ask for privacy for him during this very difficult time.”