The standoff in the 2600 block of Mission Village Drive began around 1:30 a.m., according to San Diego police Officer Robert Heims. The initial 911 call came in reporting that shots had been fired, SDPD Officer Frank Cali said.
Around 5:15 a.m., the standoff ended with police entering the apartment and determining that the man was dead from an apparent self-inflicted gunshot wound, police said.
It was not immediately clear when the fatal shot was fired because, though the initial 911 call was for shots fired, police said they later saw some movement in the apartment.
Police were unable to make verbal contact with the man throughout the standoff.
Due to the police activity, residents of neighboring apartments were evacuated. They were allowed to return to their homes just before 5:30 a.m.