WINTHROP (CBS) – Nathan Allen, the man killed by Winthrop Police after he allegedly crashed a stolen truck into a home and fatally shot two bystanders, posted photos of himself shooting what look to be real guns and playing first person shooter video games on Instagram.

On Sunday afternoon, police say the 28-year-old was carrying two handguns when he stole a truck and allegedly shot two black Winthrop residents, retired Massachusetts State Trooper Dave Green and Air Force Staff Sgt. Ramona Cooper.

The District Attorney is investigating the case as a hate crime after finding “disturbing” notes in his notebook. There were anti-semitic and racist writings with Allen’s handwriting, with some written just last week.

Neighbors at his Winthrop apartment building knew little about him.

“Very upset. Very nervous about it. It’s scary,” said neighbor Mary Harrington.

Police say Allen had no criminal record, and he he passed a background check and had a license to carry the guns. Healso earned a bachelors degree in Science from UMass Dartmouth in 2014 and a PHD in Physical Therapy from MGH Institute of Health Professions in 2021.

Nathan Allen. (Image Credit: Suffolk District Attorney)

Allen moved to Winthrop in 2019 and was married.

A woman leaving his family’s home and carrying clothes in West Wareham had no comment about Allen.

The Anti-Defamation League says to is worrisome to know there are those among us who have been radicalized to hate people because of their religion or skin color. And it is scary and dangerous not to know when they could act on that hatred.

“There are people walking around who they’re motivated by hatred, and have, at some point, been radicalized to target people because of their skin color or their religion. And what’s dangerous, and what’s scary for all of us in the public, is we don’t know when this might happen,” said Robert Trestan of the Anti-Defamation League.

At this point, police believe Allen acted alone and there is no further threat to the community.

Cheryl Fiandaca