A 17-year-old man lost his cell phone, wallet and baseball cap to a mob of four men who threatened him with a knife at 16th and Mission streets at 3:30 in the afternoon Wednesday.

After robbing the young man of his possessions, the men — all believed to be in their 20s — absconded into the BART station.

The young man reported no injuries, and no arrests have been made.

A 27-year-old man was arrested for brutally attacking a 35-year-old man and taking his money at 24th Street and Potrero Avenue just before 3 a.m. Friday.

Police report that the suspect snuck up on the victim, kicked him to the ground and proceeded to punch the victim and demand his money. The victim turned it over.

The suspect was eventually taken into custody.

Three men — two of them believed to be teenagers — held up a teenage man and woman at gunpoint at 20th and San Carlos streets at 4 p.m. Wednesday.

The young woman, 16, lost her necklace after a car pulled up, and two of men believed in to be in their late teens got out and pulled out a gun. They took the woman’s necklace and drove off in the car.

No injuries were reported and no arrests have been made.

Recent calls for service to police can be found on CrimeMapping.

Crime is trauma and the county offers different services, which can be found hereVictims of violent crime can also contact the Trauma Recovery Center at UCSF.