In brief: Bob Lee, creator of payment platform Cash App and the chief product officer at crypto company MobileCoin, was killed in a fatal stabbing in San Francisco on Tuesday morning. Tech executives, including Elon Musk and Jack Dorsey, have paid tribute to Lee, with many highlighting what they say is a violent crime problem in the city.

San Francisco police said officers responded to a report of a stabbing on Main Street at around 2.35 am on Tuesday. Officers found a 43-year-old man with what appeared to be stab wounds. They administered aid and called the paramedics, who transported the man to the hospital. He later died of his injuries.

Lee's father, Rick Lee, confirmed his son's death on Facebook. "I just lost my best friend, my son Bob Lee when he lost his life on the street in San Francisco early Tuesday Morning," Rick Lee wrote. He said his son would "give you the shirt off his back."

"He would never look down on anyone and adhered to a strict no-judgment philosophy. Bobby worked harder than anyone and was the smartest person I have ever known," Rick Lee said.

Bob Lee worked at Google during the early Android years. He later became the CTO of mobile payment company Square (now Block) to develop its Android app, and founded Cash App, which allows users to transfer cash to others and make market investments.

"Our dear friend and colleague, Bob Lee passed away yesterday at the age of 43, survived by a loving family and collection of close friends and collaborators," tweeted the official MobileCoin account.

"Bob was a dynamo, a force of nature. Bob was the genuine article. 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. Bob was made for the new world, he was the quintessential creator, leader, and consummate hacker," said Josh Goldbar, MobileCoin CEO.

NBC reports that Lee and his father had been living in Miami since October after moving from California. Bob Lee previously lived in Mill Valley, north of San Francisco across the Golden Gate Bridge. It's not clear why he was back in the Bay Area.

Twitter co-founder and Square developer Jack Dorsey paid tribute to Lee on his social network, Nostr. "It's real. Getting calls. Heartbreaking. Bob was instrumental to Square and Cash App. STL guy."

Elon Musk tweeted, "Very sorry to hear that. Many people I know have been severely assaulted. Violent crime in SF is horrific and even if attackers are caught, they are often released immediately."

"Is the city taking stronger action to incarcerate repeat violent offenders Brooke Jenkins (San Francisco District Attorney)?" Musk asked.

More than 36 hours after Lee's murder, there have been no arrests. MMA fighter Jake Shields, who says he was close friends with Lee, tweeted that the incident took place in a "good" part of the city and appeared to have been a random mugging/attack.

Insider writes that while the overall number of homicides has ticked higher in San Francisco, local authority data states that violent crime levels have remained quite stable over the past few years and compare relatively well to other big cities in the US, though property crime has increased sharply. However, many residents say these figures do not represent the real experience of living in the city, which is known for its homelessness problem.