Five people were seriously hurt, including two children, in a traffic crash Thursday afternoon in McKinley Park on the Southwest Side.
The most recent fatal attack happened early Sunday in Gage Park on the Southwest Side.
The catalytic converters were stolen from parked vehicles, Chicago police said.
In each case, someone stole vehicles left with the keys inside or running, Chicago police said.
Police asked anyone with information to call Area Central detectives at 312-747-8382.
Troopers responded to gunfire about 7:20 p.m. in the northbound lanes near Ashland Avenue, Illinois State Police said in a statement.
Ashley Williams, 16, was last seen Saturday in the 3300 block of South Leavitt Street, according to a missing persons alert from Chicago police.
A suspect was in custody after a man was shot to death Thursday night in a parking lot in the McKinley Park neighborhood on the South Side, police said.