(KRON) -- A man has been arrested in connection with a shooting that happened at the Contra Costa County Fairgrounds in September, the Contra Costa County Sheriff's Office said. Deputies found a large stash of weapons at his Pittsburg home. The shooting happened on Sept. 16 at the fairgrounds, which are in Antioch. Two people shot the victim after an argument, the sheriff's office said. The suspect was placed in critical condition after the shooting. Victim dies in overnight Oakland shooting One suspect used an illegally manufactured gun in the shooting. Detectives later determined he was illegally making and selling guns, including assault weapons, per CCCSO. Deputies searched the suspect's home on Thursday and found numerous assault weapons and a short-barreled rifle. Some of the weapons did not have serial numbers. The suspect was identified as Diego Vasquez-Gomez, 27, of Pittsburg. He was arrested on suspicion of various gun-related crimes and child endangerment. The weapons will be tested to see if they are linked to any other crimes.