An early morning shooting killed a man and critically injured a 55-year-old woman in the Mission District on Monday, according to police.

The man and woman were shot at 16th and Valencia streets at around 1:02 a.m., according to the San Francisco Police Department.

The man, whose identity has not been released by the Medical Examiner’s Office, died at the scene.

Police said the shooter is unknown.

The homicide is under investigation.

The shooting was the second homicide in days and marked the 43rd homicide of the year in San Francisco.

On Saturday night, 16-year-old Josue Mejia-Sanchez was killed in a knife attack at Mission Street and Geneva Avenue. No suspects have been arrested.

mbarba@sfexaminer.com