Colin Kroll, the co-founder and chief executive of the popular app HQ Trivia, was found dead on Sunday, apparently of a drug overdose, at his home in Lower Manhattan. He was 34.

The police said they found his body facedown on his bed after a woman called 911 and asked the police to check on him in his SoHo apartment, on Spring Street. The woman’s relationship to Mr. Kroll was unclear, but the police said she had grown worried about his well-being. The police said they found what appeared to be cocaine and heroin in the apartment.

The medical examiner was to determine the cause of death, the police said.

Before creating HQ Trivia, which live-streams 15-minute trivia shows typically twice a day to tens of thousands of mobile users, Mr. Kroll was among those who founded the six-second video app Vine, which was sold to Twitter in 2012 and closed last year.

Mr. Kroll was a fan of e-sports and live-streaming gaming platforms like Twitch, which inspired the development of HQ Trivia.