The victim was taken to John Muir Medical Center in Walnut Creek. The Contra Costa County coroner's office has identified him as 24-year-old Donovan Mumphrey.
Vallejo police Lt. Rick Nichelman said Mumphrey was shot around 11:40 p.m. during a possible carjacking attempt in the parking lot of an apartment complex at 55 Valle Vista Ave.
Police are working on a suspect description, Nichelman said. It is the 10th homicide in Vallejo this year.