A 49-year-old man was arrested after assaulting another man with a hammer early Friday morning in the San Francisco's South of Market neighborhood, police said.
At about 12:40 a.m., officers responded to a report of an aggravated assault near Division and Brannan streets, according to police.
Officers learned the victim, a 55-year-old man, had gotten into an altercation with a family member. When the suspect stepped in to stop the altercation, the victim got angry and confronted the suspect.
The suspect then picked up a hammer and struck the victim before fleeing the scene, police said.
The victim was taken to a hospital with life-threatening injuries.
Officers were able to locate the suspect and arrested him, according to police.