The attack happened near the intersection of Halsted and Diversey.
The suspect, identified as 30-year-old parolee Jose Rodriguez, is accused of grabbing a 29-year-old female from behind, threatening her with a screwdriver, and running off with her purse.
A Good Samaritan saw the attack and chased the suspect. Another witness helped tackle Rodriguez and the two men held him until police arrived.
The victim was not seriously injured.