What just happened? Colin Kroll, the 34-year-old co-founder of HQ Trivia and Vine, was found dead in his Manhattan apartment on Saturday from what appears to be a drug overdose.

The Daily Beast reports that Kroll's girlfriend had called 911 and asked police to check on him. She accompanied officers to the SoHo apartment, where he was found unresponsive on his bed. Kroll was pronounced dead by paramedics one hour later.

Narcotics and drug paraphernalia were discovered on the scene, leading police to investigate his death as a possible overdose. An NYPD official told the publication "that the drugs recovered from near Kroll included envelopes that contained white powder substances believed to be heroin or cocaine."

Yesterday, instead of streaming the game, HQ Trivia broadcast a memorial led by host Scott Rogowsky.

"We learned today of the passing of our friend and founder, Colin Kroll, and it's with deep sadness that we say goodbye. Our thoughts go out to his family, friends and loved ones during this incredibly difficult time," a spokesperson for HQ Trivia said, in a statement.

Back in 2012, Kroll co-founded the short-form video platform Vine, which was acquired by Twitter for an estimated $30 million before it launched. Kroll moved to Twitter along with Vine, but was eventually fired for what he called "poor management." He also faced allegations of inappropriate workplace behavior toward woman.

Kroll then co-founded HQ Trivia alongside fellow Vine creator Rus Yusupov. When it launched in August last year, the live-streamed quiz app that offers cash prizes of up to $100,000 went viral. Three months ago, Kroll, who had been CTO, was named CEO after Yusupov moved to the CCO position.

Kroll hit the headlines again when an HQ Trivia employee made a formal complaint against him over his conduct as a manager, but an investigation "yielded no concerns," according to Recode. Reports of his alleged behavior saw some investors reluctant to put money into parent company Intermedia Labs.

HQ Trivia's user numbers have been shrinking lately, and its position in the app store has been falling. The company launched a new game called HQ Words in October.

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