San Francisco medical staff worked tirelessly for over four hours trying to save Cash App founder Bob Lee’s life — stapling his heart and placing a chest tube in him before he passed away on an operating table, autopsy records show.

Lee was visiting the city when he was stabbed three times early April 4 and left for dead. The 43-year-old divorced tech boss made a frantic 911 call just after 2:35 a.m. to seek help, before collapsing to the ground in front of a residential apartment.