Police in Connecticut said on Monday the father of one of the 20 children killed in the Sandy Hook elementary school shooting in 2012 had been found dead in an apparent suicide.

Newtown police say the body of Jeremy Richman, 49, was found inside an event center where he had an office.

Richman was the father of first-grader Avielle Richman. He and his wife created the Avielle Foundation, a group dedicating to preventing violence by seeking a better understanding of brain health.

Neil Heslin, whose son Jesse Lewis was also killed at the school, said Sandy Hook families’ grief has been compounded by the publicity and conspiracy theories surrounding the tragedy.

Heslin noted that Richman was among Sandy Hook relatives suing the conspiracy theorist Alex Jones for saying the Newtown shooting never happened.

“Every day you get up, you expect to get punched in the chin with something,” Heslin said. “I give Jeremy credit for what he accomplished with his work and his amazing strength that grew through the years.”

The governor, two US senators and other elected officials expressed condolences.

“My god,” Senator Chris Murphy wrote on Twitter. “This is awful, horrible, devastating news.

“Jeremy was a good friend and an unceasing advocate for better research into the brain’s violence triggers. He was with me in my office two weeks ago, excited as could be about the Avielle Foundation’s latest amazing work.”

Lieutenant Aaron Bahamonde of Newtown police said Richman left a suicide note, but not disclose its contents.