Law enforcement officials announced Thursday they had detained a friend of the well-known tech executive and would charge him with murder nine days after the fatal late-night stabbing of Cash App founder Bob Lee. 

Mr Lee was 43 years old. 

Nima Momeni, a 38-year-old computer entrepreneur and consultant whom family members claimed Mr Lee knew personally, was named by the authorities as the suspect in the killing.

Mr Momeni, the proprietor of an enterprise tech company in Emeryville, an East Bay community, was apprehended following an investigation that took place in opposition to vehement assertions that the killing was indicative of a city where the professional class was susceptible to arbitrary attacks.

The suspect was lodged in the San Francisco County Jail on Thursday morning and will be charged with murder on Friday.

Criminal records show that Mr Momeni was given a misdemeanour charge in 2011 for carrying a switchblade, but the case was later dropped after he accepted a plea agreement.

Law enforcement representatives acknowledged growing worries about random violence and property crimes in the city at a news conference, but they claimed that Mr Lee’s killing did not follow that trend.

“This has nothing to do with San Francisco — it has to do with human nature,” the city’s police chief Bill Scott said.

Mr Lee, the founder of Cash App and former chief technology officer at Square, was stabbed to death near downtown San Francisco.

Police were called to a stabbing report in the city’s Rincon Hill neighbourhood, in the 300 block of Main Street, at around 2:35 a.m., according to media reports. Mr Lee was discovered at the scene and taken to a nearby hospital, where he succumbed to his wounds later.