SAN FRANCISCO (KRON) — Bob Lee, founder of Cash App, was stabbed to death Tuesday morning on Main Street in San Francisco, not far from the Bay Bridge. In the aftermath of Lee’s shocking death, friends and co-workers say they can’t understand why this would happen. They say they’re trying to grapple with the fact that someone stabbed their friend to death.

“He was incredibly personable, wonderfully friendly, and just a force of nature,” said friend, Doug Dalton.

When you talk to the inner friend circle of Lee, you’ll hear nothing but positives. Dalton met the 43-year-old while they were both working in tech.

“Once you made a friendship with Bob you were friends with him for pretty much forever. He was a very sweet thoughtful person,” Dalton added.

The last photo Dalton has with his friend was taken at a birthday party dinner over the weekend. Lee was found by San Francisco police Tuesday shortly after 2:30 a.m., stabbed to death on Main Street in SOMA.

His death occurred in the same district that Supervisor Matt Dorsey represents.

“This is not a city where anybody should fear for their lives at 2:30 in the morning. This is a city that has a vibrant nightlife and we should be safe 24 hours a day,” Dorsey said.

Lee had a successful career in tech as the founder of Cash App, former Chief Technology Officer of Square and Chief Product Officer at Mobile Coin. Former MMA fighter Jake Shields was a friend of Lee’s and says crime was the reason Lee left the Bay Area.

“He did comment on San Francisco deteriorating,” Shields said, “which is why he had actually just relocated to Miami. So, I’m not sure why he’s even back there. I think he had a little business back in San Francisco for a couple days.”

According to his co-workers, Lee was in town for a Mobile Coin leadership summit. His death caused a firestorm of posts on social media about violent crimes in San Francisco.

District Attorney Brooke Jenkins posted on Twitter Wednesday, saying:

“Protecting public safety and holding violent/repeat offenders accountable is a top priority for my administration.”

The DA extended her condolences to Lee’s friends and family who are trying to figure out the tough question of why.

“I can’t imagine anyone targeting Bob,” Dalton said. “He was not a person who garnered any sort of animosity towards people. If anything, he garnered respect and love and people really enjoyed hanging out with him.”

Supervisor Dorsey said today that investigators believe surveillance video might have captured the stabbing on the 400 block of Main Street. Anyone with video or information about the stabbing can contact the San Francisco Police Department.