A 21-year-old man was found dead in his Mission Beach apartment Sunday morning, according to detectives from the San Diego Police Department's Homicide Unit.
Officers and paramedics responded to a call in the 3600 block of Bayside Lane shortly after midnight. Paramedics found the man and tried to save him but they were unsuccessful.
Brandon Callanan, 29, was arrested in connection with the case, police said.
Police say he went to the victim's apartment and the two started fighting. At the end of the fight the victim was unresponsive and Callanan left. Police arrested him an hour later after he returned to the apartment, officers said. Callanan was booked into County Jail.
The cause of the victim's death is not known. An autopsy will be performed.The victim's name will not be released until family members are notified.