Bob Lee, the chief product officer at MobileCoin, was killed in a fatal stabbing in San Francisco.

On Tuesday morning, at 2:35 a.m., the San Francisco Police Department responded to a report of a stabbing near the 300 block of Main Street in SoMa. He was taken to a hospital but succumbed to his injuries.

Shortly after, NBC Bay Area reported that the victim of the stabbing was Bob Lee, 43. MobileCoin confirmed the information in a statement sent to Bloomberg and ABC7 News.

Before joining MobileCoin, Bob Lee worked at Google for the first few years of Android, focusing on core library development. He then joined Square, the payment company that later became Block, to develop its Android app. He became the company’s first CTO and also created Cash App.

Bob Lee, also known as ‘Crazy Bob,’ was an investor in tech startups as well. According to his LinkedIn profile, he invested in SpaceX, Clubhouse, Tile, Figma, Faire, Orchid, Addressable, Nana, Ticket Fairy, Gowalla, Asha, SiPhox, Netswitch, Found and others.

Following the news, there was an outpouring of grief in the tech community. “It’s real. Getting calls. Heartbreaking. Bob was instrumental to Square and Cash App. STL guy,” Jack Dorsey, the CEO of Block, wrote on nostr.

“So sad to hear of @crazybob’s untimely passing. I first met him in summer 2006 — he didn’t care that I was only 14 and we talked tech / geeked out about programming. We remained connected over the years and he was an early supporter of Figma. It’s so hard to believe he is gone,” Figma CEO Dylan Field wrote on Twitter.

“What a tragedy. I remember Bob’s code that generates certain numbers. Bob’s code is in Java, yet uses clever backtracking techniques to achieve the best performance among many solutions in all kinds of languages,” hintymad wrote on Hacker News.

No arrest has been made in the case and the San Francisco Police Department hasn’t shared any additional details.