28-year-old Nathan Allen was identified as the culprit behind a Massachusetts shooting that left two Black people dead. Investigators are looking into the matter as a hate crime after finding “some troubling white supremacist rhetoric” in the gunman’s handwriting, according to NBC News.

Suffolk County District Attorney Rachael Rollins, who first identified Allen, said during a press conference on Sunday, June 27, that investigators found “antisemitic and racist statements against Black individuals.” Allen was shot dead by police officers on Saturday afternoon shortly after he hijacked a plumber’s truck, crashed it into a house, and then shot David Green and Ramona Cooper multiple times in Winthrop, just outside of Boston, according to Winthrop Police Chief Terence Delehanty.

David Green, 58, a retired Massachusetts State Police officer and Ramona Cooper, 60, an Air Force veteran who still worked with the military, were found viciously slain by Nathan Allen. Green was shot four times in the head and three in the torso, and Cooper three times in the back. 

“He walked by several people that were not Black and they are alive. They were not harmed,” Rollins said. “They are alive and these two visible people of color are not.”

Rollins delivered a statement on Sunday, describing a note Allen wrote about white people being “apex predators” and highlighting how he drew Nazi swastikas. 

There were no specific details about where the writing was found, but added that authorities are still investigating a motive for the shooting.

Before crashing into the house, Allen allegedly drove the stolen truck into another vehicle with two passengers, Delehanty said. The two people were taken to the hospital with injuries that were not life-threatening.

Rollins also detailed that Allen was married, employed, had a Ph.D. and no criminal history, saying that he “likely appeared unassuming.”

“This is a sad day,” Rollins said Sunday. Cooper and Green “protected our rights. They fought for us to be safe, to have the opinions that we have — and they were executed.”