What made Jason Hendrix snap?

The suspect ... Jason Hendrix, who was killed in a police shootout. Picture: CNN Source: Supplied

A TEEN boy has been killed in a US police shootout after allegedly slaying his parents and younger sister for taking away his computer and phone privileges.

Jason Hendrix, 16, of Corbin, Kentucky, was suspected of killing his family execution-style before fleeing his home, and leading police on a high-speed chase.

Baltimore County Police also said Jason shot and wounded a police officer in the shootout after crashing his parent's green Honda Pilot into a silver sedan.

At least six officers opened fire on Jason, who was pronounced dead at the scene.

Maryland State Police said they initially wanted to pull him over for speeding.

The shootout led police to search the teen's home more than 500 miles (804km) away in Corbin.

There, authorities found the bodies of his parents Kevin and Sarah Hendrix and their daughter, Grace, about age 12, Corbin Police Chief David Campbell said.

The father, wearing a sport coat and tie from work, was shot twice in the head, Campbell said. He added that the mother was shot twice in the face and the girl twice in the head and once in the arm.

The car chase ... Jason Hendrix fled the scene of the murder. Picture: CBS Baltimore Source: Supplied

Jason had fled the gruesome murder scene in his parent's car, armed with four weapons and a backpack full of ammunition, Campbell added.

He was carrying four .38-caliber handguns, a 9mm handgun and a shotgun, according to police. Two of the weapons — the 9mm and one of the .38-caliber guns — were loaded, police said.

"It's concerning that any 16-year-old would be driving around with that kind of firepower," said Cpl. John Wachter, spokesman for the police.

"Nobody should have been running around with that many weapons unsecured."

Police Chief David Campbell said all the evidence pointed to Jason being the suspect.

Police didn't know why the suspect decided to flee to the East Coast. The family had no relatives in Baltimore, Campbell said.

"We have no clue why he went up there," the chief said.

As for a motive, Campbell said the teenager was angry at his parents for taking away his computer privileges days before the slayings.

"The mother had talked to a co-worker and told her that he was really mad about that," the chief said.

Shots fired ... the back of Jason Hendrix's getaway car. Picture: CBS Baltimore Source: Supplied

Jason met up with friends at a church evening and showed no signs of distress. "They said he was just like he usually is," Campbell said.

Family and friends in Corbin could not understand the series of events, recalling that Jason was a regular churchgoer and was known for his politeness.

Drew Mahan, the founding pastor of Forward Community Church where the Hendrixes attended, said officers questioned him extensively about Jason on Saturday night after discovering the bodies. He described Jason as a faithful member of his three-year-old church, which holds services at a local movie theatre.

Jason would arrive at the theatre every Sunday at 7am to help set up the church's equipment and was baptised at a service in December.

The crash site ... police investigate the crash after the shootout. Picture: CBS Baltimore Source: Supplied

"People want to ask questions. Why? How? I simply looked at folks today and said, 'I don't know," Mahan said after finishing the Sunday morning service.

"The guy has been here. He's been an influence on our students, he's been an influence on my own kids. They love him."

His parents Kevin and Sarah Hendrix were beekeepers who sold honey in the local farmers market, and Grace Hendrix was a middle school cheerleader.

A spokesman for Union College in Barbourville confirmed Sarah Hendrix was a professor at the school.

Michelle Payne, a 30-year-old mother who lived across the street from the Hendrixes, said they were "your classic small town family," adding she had not seen the family since Tuesday night when Kevin was walking the family's dog.

The police officer who was shot was treated at the University of Maryland Shock Trauma Center and released, according to a statement.

Officials said the six Baltimore County Police officers who fired their weapons during the shootout will be placed on administrative status pending a review.