POLICE said a strong-armed robber who lost his keys while beating up a woman for her purse in Upper Darby on Saturday returned to the crime scene to search for his keys and was nabbed by a vigilant cop in an undercover car.

Cordell Kelly, 19, of Upper Darby, allegedly beat a 30-year-old woman for her Coach purse in the middle of Timberlake Road near Midway Avenue about 2:30 a.m. Saturday.

Unbeknownst to Kelly, his keys fell from his pocket during the assault, and on the keychain was a Modell's MVP card with Kelly's address on it, Upper Darby police Superintendent Michael Chitwood said.

On a hunch that Kelly might return for his missing keys, Officer Christopher Karr picked up an unmarked car at police headquarters and waited for Kelly to return.

"About an hour later, here comes a fellow looking underneath the cars on the street where the robbery took place," Chitwood said. "Thank God he's not a rocket scientist."

Karr took Kelly into custody, and police who executed a search warrant at the home where Kelly lives with his sister found the victim's purse in Kelly's room, police said.

Kelly was charged with robbery, theft and related offenses.

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