A 27-year-old man was robbed at gunpoint at 20th and Valencia streets between 2:30 and 3:30 a.m. on Thursday.
As the victim was walking, police said, a 40-year-old man began walking alongside him. After a while the suspect told the man to put his backpack down and walk away.
The victim complied, turned and saw the suspect pointing a handgun at him.
The suspect got away with a watch, a tablet computer and a cell phone.
A 24-year-old man suffered stab wounds to his arm and was taken to the hospital Thursday night, police said.
Shortly before midnight on Thursday, at 22nd and Bartlett streets, the victim got into a verbal argument with two suspects described as 25-year-old men, according to police records.
One of the suspects stabbed the victim in the arm; the injuries inflicted were not life-threatening. Both suspects then fled on foot.