Bob Lee, the creator of Cash App and chief product officer of MobileCoin, was killed early Tuesday morning in a stabbing in San Francisco, law enforcement officials confirmed. He was 43 years old.

The attack took place in the San Francisco neighborhood of Rincon Hill at around 2:30 in the morning. San Francisco’s District Attorney, Brooke Jenkins, has stated on Twitter that no arrests have yet been made.


Lee joined MobileCoin—the mobile-first cryptocurrency payments platform—as a part-time advisor and early-stage investor in February 2021. He went on to become MobileCoin’s CPO in November of that year, where he helped launched MobileCoin’s digital wallet Moby.

"With financial data security more important than ever, developing end-to-end encrypted payment technology isn't just smart—it's our responsibility," Lee said at the time. "The traditional financial system leaves behind hundreds of millions of 'unbanked' people worldwide and consequently excludes them from the associated benefits."

In addition to serving as the first chief technology officer at Square, Lee previously led the core development team for Android at Google. He also founded a location-centric social network called Present, and both advised and invested in companies like Figma, Clubhouse, Beeper, and Faire. During the COVID-19 pandemic, he assisted the World Health Organization with their mobile app and led development for an at-home testing company.

Grieving the loss of Lee on Twitter, MobileCoin Founder Joshua Goldbard said that Lee “was so much more than a technologist,” describing his late friend as a visionary and someone who cared deeply about people’s right to privacy.


“His brain moved at an unbelievable velocity,” Goldbard recalled. “There will never be anyone quite like him.”

At the financial services platform Square—known today as Block—Lee served as the company’s first CTO. During his time there, he created Cash App, which is one of the most popular applications for transferring money between individuals, and also supports the purchase of stocks and Bitcoin.

Former Twitter CEO and Block Founder Jack Dorsey said Lee’s death was “heartbreaking” on Nostr, the decentralized Twitter alternative. He also posted a picture of the first transaction to ever take place using Cash App, recalling the time Lee sent Dorsey $4.

Bill Barhydt, the CEO of Abra—a cryptocurrency-focused payments company and digital wallet provider—said the loss of Lee was “devastating” and that he didn’t deserve to be killed. Responding to another Twitter user, Barhydt said he was “heartbroken for [Lee’s] family.”

It was unclear Wednesday whether police had established a possible motive behind Lee’s death. The San Francisco Police Department did not immediately respond to requests for comment from Decrypt.

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