CHICAGO (CBS) — A 7-Eleven clerk was stabbed outside a Loop convenience store early Monday, after a thief caught in the act threw a Lottery machine at him, police said.

Shortly after 3 a.m., the clerk caught a person trying to steal items from the 7-Eleven at the corner of State and Jackson, according to Chicago police.

The clerk stopped the theft, but police said the thief returned about 10 minutes later, and threw a Lottery machine at the clerk. The fight continued outside the store, where the thief stabbed the clerk in the arm.

The attacker fled the scene, and the clerk was taken to Northwestern Memorial Hospital, where he was in good condition.

Area Central detectives were investigating.