“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.

Kroll stood out for his connection to two breakthrough mobile apps. Twitter purchased Vine, which allowed users to post short looping video clips, for an estimated $30 million in 2012, but then shut the service in 2017. HQ Trivia, with its by-appointment contests, rapidly became an internet industry and US cultural phenomenon, with as many as half a million people using it at a time. “HQ blasted out of obscurity this fall to become the best worst thing on the internet,” the NY Times wrote in January. “It’s the most popular app that barely even works.”

HQ Trivia has been going through turmoil of late. The app plummeted in popularity this year, falling from its place in the top 10 iPhone games in January to fluctuating between 250th and 500th most popular gaming app in recent months, according to TMZ. The company also underwent a tumultuous change in CEO over the summer.

Kroll replaced the outgoing CEO, only to be the subject of a formal human resources complaint by a HQ Trivia employee over his conduct as a manager. A company spokesperson told Recode that an external investigation “yielded no concerns.”

Multiple sources told Recode that Kroll was fired from Twitter for being a bad manager, and had a reputation for inappropriate behavior toward women at the company, as well as at Vine. At least three investors declined to put money into Intermedia Labs, the company behind HQ Trivia, when Kroll’s alleged past conduct came to light, Recode reported.

Intermedia Labs didn’t immediately respond to an email requesting comment about Kroll’s death.

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