Trenton, New Jersey - An "extremely dangerous" suspect was taken into custody in New Jersey on Saturday after allegedly shooting dead three family members, authorities said, following an hours-long effort to detain him.

Andre Gordon (26) "surrendered peacefully," Trenton Police Department spokesperson Lisette Rios told AFP, after a trail of violence that triggered shelter-in-place orders in two states.

Authorities said Gordon, who is believed to be homeless, began the day by carjacking a vehicle in Trenton before driving some 40 miles to the northern Philadelphia suburb of Levittown.

There, police said, the suspect killed two people – identified as his 52-year-old stepmother and his 13-year-old sister.

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Three others, including a minor, managed to hide "as he went through the house searching for them," Bucks County, Pennsylvania district attorney Jennifer Schorn said in a briefing.

The suspect then drove to a nearby residence where he broke in before shooting and killing a 25-year-old woman – who Schorn said was the mother of his two children – before bludgeoning her mother with the butt of his rifle. She was expected to recover.

Driving to a nearby discount store, the suspect carjacked a 44-year-old man before fleeing. The man was not injured, according to Falls Township, Pennsylvania Sheriff Nelson Whitney.

The suspect then drove across the state line back to Trenton, where police believed he had barricaded himself in a three-story house.

Whitney had said the suspect was believed to be armed with an AR-15 style assault rifle, and police described him as "extremely dangerous."

For several hours, they appealed to him to surrender, after SWAT officers evacuated people in the home through a second-story window.

"Andre, get away from the windows. We know you're inside. If you'd like to surrender, dial 911 now," police said over loudspeaker. "You're a young man, you have too much to live for."

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Later on Saturday, Gordon was "located at another location in Trenton," Rios said.

Trenton Police Director Steve Wilson said Gordon was uninjured and walking along a street when a patrol officer approached him.

Gordon had apparently slipped out of the house before police had completed setting up a perimeter, Wilson said.

Because the suspect crossed state lines, federal authorities – including the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives – were working the case, along with local, county, and state police.