BOSTON (NYTIMES) - The authorities in Winthrop, Massachusetts, are investigating whether a white man who shot and killed two black people last Saturday (June 26) after crashing a stolen truck into a house was acting out of racial and religious hatred.

The suspect, Nathan Allen, 28, had made "anti-Semitic and racist statements against black individuals", said Ms Rachael Rollins, the district attorney in Suffolk County.

She said investigators had found "some troubling white supremacist rhetoric" in Allen's own handwriting. She did not say where investigators found these writings.

Ms Rollins said her office was investigating the shooting as a hate crime and believed Allen had acted alone.

Allen stole a large truck owned by a plumbing and drain company and rammed it into a home in Winthrop, a neighbourhood about 11km east of downtown Boston, the authorities said.

He then fled on foot, the Winthrop Police Department said in a statement.

The shooting occurred at the intersection of Shirley and Cross streets at 2.41pm last Saturday, the authorities said.

Allen, who had a licence to carry a gun, began to shoot his weapon as he fled, but he walked by several people who were not black and did not shoot them, Ms Rollins said.

The victims were Mr David Green, a retired Massachusetts State Police officer with 36 years of experience, and Ms Ramona Cooper, a 60-year-old US Air Force veteran who was still working with the military, Winthrop police officials said during a news conference on Sunday.

Ms Cooper was shot three times in the back, Ms Rollins said.

Mr Green, who lived in the neighbourhood, tried to stop Allen but was shot four times in the head and three times in the torso, Ms Rollins said.

An officer then shot and killed Allen, the authorities said.

Ms Rollins said investigators were not sure why Allen was driving towards the neighbourhood at Shirley and Cross streets. But she added that there are several synagogues in Winthrop.

Mr Green was pronounced dead at the scene, and Ms Cooper was taken to hospital, where she later died, the authorities said.

"He was heroic in the 36 years he gave to law enforcement, just as Ramona Cooper serving our country and the Air Force was a hero as well," Ms Rollins said. "It's just a really tragic day in Winthrop."