A man who was fatally stabbed early Tuesday near downtown San Francisco was tech executive Bob Lee, the founder of Cash App and former chief technology officer of Square, sources told NBC Bay Area.

The San Francisco Police Department said officers responded to a report of a stabbing at around 2:35 a.m. Tuesday. They found a 43-year-old man with apparent stab wounds, police said.

The man was taken to a hospital with life-threatening injuries and later died, police said.

Police did not name the man, but sources identified Lee, who was serving as the chief product officer of MobileCoin, as the victim to NBC Bay Area.

In a statement Wednesday, the chief executive of MobileCoin said that Lee “passed away yesterday” and praised his business acumen.

“Bob was a dynamo, a force of nature. Bob was the genuine article,” Josh Goldbard said. “He was made for the world that is being born right now, he was a child of dreams, and whatever he imagined, no matter how crazy, he made real.”

As of early Wednesday, no arrests appeared to have been made.

Police said Tuesday that the incident was being investigated by the department’s homicide detail.

Tributes have poured in on social media for Lee, with former MMA fighter Jake Shields remembering the tech executive as a “loyal friend.”

In an earlier tweet, Shields had said he had “just found out my good friend was killed last night” while walking in a “‘good’ part of the city.”

Responding to Shields’ tweet, Twitter chief Elon Musk said he was “very sorry” to learn of Lee’s death.

This story first appeared on NBCNews.com.

This article was originally published on TODAY.com