Colin Kroll, the co-founder of HQ Trivia and now defunct video platform Vine, died Saturday at the age of 35.

The New York Police Department said officers went to Kroll's Manhattan apartment early Sunday after getting a call asking for a wellness check on him.

They found him unconscious and unresponsive on his bed.

He was pronounced dead at the scene. The medical examiner's office will determine the cause of death.

According to TMZ, who first reported his death, police were alerted by his girlfriend, who was unable to get in contact with him.

TMZ cited a police source as saying drug paraphernalia was found nearby Kroll's body, and he was using cocaine and heroin.

Kroll was the chief executive of the trivia app, which live-streams short trivia shows to users and became popular after its release in 2017. According to a report last month by Recode, Kroll had recently faced a complaint from an HQ employee over his "aggressive management style."

The app has been declining in popularity this year, falling from Apple's top 10 most downloaded games list to somewhere between No. 250 and No. 500.

Kroll also was a founder of Vine, which was an app built around six-second videos, and worked for a period at Twitter.

In February, Recode published a report that Kroll had shown "inappropriate behavior toward women" while working as a manager at Twitter-owned Vine. Though he denied the accusations, Kroll later said he had been fired from Vine for "poor management" and that his words and actions "made some feel unappreciated or uncomfortable."