Kroll was found dead in his New York City apartment on Dec. 16

Colin Kroll’s cause of death has been revealed.

The 34-year-old entrepreneur behind popular apps such as Vine and HQ Trivia — who was found dead in his Manhattan apartment two months ago — died of an accidental overdose of fentanyl, fluoroisobutyryl fentanyl, heroin, and cocaine, PEOPLE confirmed.

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The New York City Office of Chief Medical Examiner ruled in a statement released Tuesday that Kroll’s death was accidental and due to acute intoxication from the mixed drugs.

On Dec. 16, Kroll was found unresponsive in his bedroom and was declared dead at the scene by EMS responders, a New York City Police Department spokesperson confirmed to PEOPLE, adding that preliminary results suggested that Kroll overdosed.

Image zoom Colin Kroll Getty Images

In a statement given to PEOPLE in December, a spokeswoman for the popular trivia app said, “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.”

Following the news of his death, Kroll’s Vine and HQ Trivia co-founder, Rus Yusupov, also reacted in a tweet.

“So sad to hear about the passing of my friend and co-founder Colin Kroll,” he wrote. “My thoughts & prayers go out to his loved ones. 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.”

Kroll co-founded Vine, which he left in 2014 and which was later discontinued, Time reported. Kroll started as HQ Trivia’s chief technology officer in 2017 and became CEO in September, according to Business Insider.

An HQ Trivia employee filed a complaint against Kroll for “aggressive management style” in August, Recode reported in November. In December 2017, Recode reported that Kroll was previously ousted from Twitter — which acquired Vine — for his management approach.

“As reported in the media, I was let go from Vine four years ago for poor management. It was a painful experience, but an eye-opening one that served as a catalyst for professional development and greater awareness in the office,” Kroll told Axios in March.

“I now realize that there are things I said and did that made some feel unappreciated or uncomfortable,” he continued. “I apologize 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.”