PHENIX CITY, Ala. (AP) — Owners of an Alabama pawn shop say a homemade pipe bomb blew up on their front door. The explosion is the latest in a string of attacks aimed at breaking into the store.

Uptown Jewelry and Pawn’s owners in Phenix City told WTVM-TV (http://bit.ly/1HOiES7 ) a homemade explosive device was used to try to break into the store Saturday night. The bomb was made out of a soda bottle filled with tacks and nails. Store employees say someone previously tried to shoot off the lock and run a car through the wall.

Police are investigating the attacks. The store owners are offering a $500 reward to anyone with information leading to an arrest.