Authorities say 51-year-old Suzanne Siadat was kneeling at Queen of Peace Catholic Church on Saturday when she heard someone rustling through papers that she had on the pew beside her.
She turned and saw a man, who then grabbed her purse from the pew. Siadat tried to get the purse back, but he pushed her down and ran away, injuring her knee.
Police later found the suspect in an alley and recovered the purse in a garbage bin.
The suspect was identified as 44-year-old Ronald Slavin, who had just been treated at a hospital for injuries he sustained in a scuffle with police the night before.