A man suspected of killing  two family members and the mother of his children has been arrested in New Jersey after a standoff with police.

Police said the man was found near a house state capital Trenton, were he was believed to have barricaded himself, and was taken into custody.

No-one else was injured.

Steve Wilson, police director for the city of Trenton, said the man was found near a house were he was believed to have barricaded himself and was taken into custody.

Wilson added that he did not believe the suspect was armed at the time.

The suspect was identified earlier as 26-year-old Andre Gordon Jr.

Authorities believe he killed his stepmother, his teenage sister and the mother of his children in shootings that stretched into two homes in eastern Pennsylvania’s Falls Township, Bucks County District Attorney Jennifer Schorn said.

Officials said they couldn’t yet speak to a motive for the attacks. While Gordon had had some minor brushes with the law, they were “nothing that would indicate that anything like this would happen,” Falls Township Police Chief Nelson Whitney said at a news conference.

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Police said Gordon was believed to be homeless.

The mayhem forced the cancellation of a St. Patrick’s Day parade and shut down a Sesame Street-themed amusement park. Authorities in Pennsylvania’s Bucks County issued a shelter-in-place order for some areas for several hours.

After fleeing in a stolen car, then taking another in a carjacking in a store parking lot, Gordon went to the home in nearby Trenton, authorities said.

By mid-afternoon, officers surrounded the house on a taped-off block, calling to Gordon through a loudspeaker and trying to persuade him to come out.

Shaun Murphy, who lives in Levittown, said he was headed to the local St Patrick’s Day parade when he saw that the road had been blocked.

“All the neighbours were outside wondering what was going on, and then we got the notice about shelter in place,” Murphy said.

Police in Middletown Township, Pennsylvania, said Gordon has ties to addresses in Bucks County and Trenton and “stays in Trenton primarily.”

-with AAP