Police received a 9-1-1 call at 8:23 a.m. about a house fire in the 200 block of East 15th Street.
When they arrived they discovered a man who was suffering from head trauma after his girlfriend had allegedly struck him.
He explained to officers that she had reached into a window and lit a blanket that was covering the window on fire, police officials said.
"There was a 1-year-old baby and two adults inside the home when the fire was started," said Police Lt. Mike Madden. "Given the possibility of imminent threat to those inside she was arrested on suspicion of attempted murder."
The woman was arrested and booked on suspicion of arson, attempted murder and domestic violence. Her name was not immediately available at the time of this report.