RANCHO CUCAMONGA, Calif. (KABC) -- A man who walked in on a burglary at his Rancho Cucamonga home fired his gun at the suspect after the alleged burglar shot at him early Sunday morning.Authorities said around 12:41 a.m. a resident in the 1600 block of Brindisi Way reported coming home and finding his front door open.The resident told authorities as he approached the door, the burglary suspect shot at him from inside the house. The homeowner then grabbed a gun from his car and shot at the suspect through the front door. That is when the homeowner called police, authorities said.Authorities arrived and set up a perimeter around the home, believing the suspect barricaded himself inside the house. When authorities did not receive a response, a robot was used to check the house.The house was cleared and authorities began investigating the scene.It was determined the homeowner may have interrupted a burglary in progress. It was unclear if the suspect was struck.The investigation was ongoing.