A West Side man used a stun gun to rob a 73-year-old woman this week but witnesses chased the attacker, caught him and held him until police arrived, police said today.

Corey D. Perkins, 18, faces a charge of armed robbery with a dangerous weapon in the attack about 4:45 p.m. Monday, police said.

Perkins, of the 1200 block of North Long Avenue, is accused of robbing a woman in the 4400 block of West Armitage Avenue in the Hermosa neighborhood.

Perkins came up to the woman as she was walking, took out a stun gun and began using it on her, police said. At the same time, he tried force the woman to give up her purse, police said.

When the woman collapsed, Perkins took her purse and ran off, as several witnesses tried to stop him, then gave chase, police said. Perkins fled west from the scene of the attack, said Police News Affairs Officer Amina Greer. The witnesses caught up with Perkins nearby, and held him until officers from the Grand Central District arrived, police said.

Witnesses and the victim identified Perkins as her attacker, and he was charged Tuesday, police said.

Perkins was scheduled to appear in Cook County Central Bond Court today.