Colin Kroll, co-founder of the Vine video app and the HQ Trivia game, has been found dead in his Manhattan apartment of an apparent drug overdose. He was 34.

New York Police Department officers responded early on Sunday to a call by Kroll’s girlfriend who was concerned about him.

The police found him unresponsive in his SoHo residence and emergency staff pronounced him dead at the scene.

An NYPD spokesman said the department was awaiting results of the medical examiner’s report to determine cause of death but confirmed that drugs appeared to be involved. Police found Kroll’s body surrounded by drug paraphernalia, TMZ reported.

Kroll’s latest venture was HQ Trivia, where he served as CEO of the company he co-founded with Rus Yusupov.

HQ Trivia became a viral hit after launching in 2017 as a live-streaming game show that doles out real cash to player – a format that’s been widely copied.

In a tweet Sunday, Yusupov wrote, “I will forever remember him for his kind soul and big heart. He made the world and internet a better place. Rest in peace, brother.”

HQ Trivia also posted a statement on Twitter about Kroll’s death, saying: “Our thoughts go out to his family, friends and loved ones during this incredibly difficult time.”

Kroll had been Vine’s general manager for a few months before he was fired by Twitter in 2014.

In a statement earlier this year, Kroll acknowledged that: “I was let go from Vine four years ago for poor management. I now realise that there are things I said and did that made some feel unappreciated or uncomfortable.

“I apologise to those people. Today, I’m committed to building HQ Trivia into a culture-defining product and supporting the dedicated team that makes it all possible,” he said.

Before co-founding Vine, Kroll was CTO of Gilt Groupe’s Jetsetter travel site and mobile app where he also worked with worked with Yusupov and Hofmann.

Prior to that, Kroll was an engineering manager in Yahoo’s search and advertising technology group; he joined Yahoo with the Yahoo’s 2007 acquisition of Right Media, where Kroll had been a software engineer.

Kroll studied computer science at Oakland University in southeastern Michigan, according to his profile on Crunchbase.

-Reuters