Michael L. Dixon, 37, of the 1300 block of West Estes Avenue, is charged with aggravated criminal sexual assault, attempted robbery and battery, police said.
The woman had entered the lobby of an apartment building in the 1400 block of West Albion Avenue around 4:30 a.m. Sunday when Dixon pushed her against the wall and assaulted her, police said. "I have a gun. Don't scream. Give me your money (expletive)," Dixon said, according to a police report.
The woman tried to fight him off, hitting him in the head with her keys and kicking him, and Dixon ran out of the lobby, police said. The woman contacted a family member who told her to call 911.
The woman gave dispatchers a description of the attacker, and police spotted someone matching it riding a green mountain bike in the 6800 block of North Sheridan Road, police said.
Dixon was charged Sunday afternoon and was ordered held in lieu of $500,000 bail on Monday, officials said.