HOUSTON, Texas (KTRK) -- Authorities say a security guard opened fire on a group of men who attacked him after they refused to leave the basketball court at an apartment complex in southwest Houston.This happened around 8:50 p.m. Thursday on Dunvale near Richmond.According to police, the four men, who do not live at the complex, were repeatedly told to leave several times before for trespassing.In the incident this time, the guard went up to the group and told them to leave. Witnesses say that's when the men beat him.The guard allegedly pulled out his gun and fired. One of the men was shot. He's recovering in the hospital from a graze wound.A second man in the group stayed behind to talk to officers. The other two ran away.At this time, no charges have been filed against the guard or the group.