At least one possible shooter was shot, Guglielmi said.
Police Activity: Reports of shots fired in the vicinity of 26th and MI near Mercy Hospital. Chicago police confirmed that the gunman and the woman shot in the parking lot had been involved in a relationship. Chicago Mayor Rahm Emanuel said a doctor and a pharmaceutical assistant were the other victims.
Witness Steven White told CNN's Ryan Young that he was in the emergency room when he saw the shooter firing at police.
Johnson said they received a 911 call about the altercation in the parking lot, and within seconds, they received a second call about shots fired in the parking lot.
Sue Jimenez, the manager of Kozy's Cyclery bike shop near the hospital, said she heard multiple gunshots separated by pauses.
The suspected gunman at Mercy Hospital is dead, according to Chicago Police.
Mercy has a rich history as the city's first chartered hospital.
One employee of the hospital's family clinic heard eight or nine shots.
"I could tell he was now inside the lobby". As the violence unfolded, a hospital employee locked the doors to the waiting area. As police officers arrived, he exchanged gunfire and then entered the hospital where the gunman died. Guglielmi had urged citizens to avoid the area.
Television footage showed several people, including some wearing white coats, walking through a vehicle park with their arms up.