At about 5 p.m. the Vallejo Police Department responded to a report of shots fired in the 100 block of Carolina Street in the vicinity of the Marina Heights Apartments.
Officers searched the area for about 30 minutes, but were unable to locate any victims or suspects in connection with the shooting, police said.
A short time later, officers received a second call reporting that an unresponsive man with gunshot wounds was found inside an apartment unit, officers said.
Police responded to the apartment and found the victim suffering from what appeared to be at least one gunshot wound.
Emergency medical crews were called to the scene and the victim was pronounced deceased, according to police.
The victim's name is being withheld pending positive identification and notification of his family.
No suspects are in custody and the motive for the shooting remains under investigation.
Anyone with any information regarding this fatal shooting is encouraged to call Vallejo police Detective Raul Munoz at (707) 648-4531.