Authorities say security members were locking the gates to Rotary Park East on Cedar and Paul Avenues shortly before 11:00 pm on Thursday when they saw a man locked inside a car.
Fresno police officers were called to the scene to help.
When investigators were able to open the car door, they found a man inside, gasping for air with blood on his head.
Police say he had been shot. He was rushed to a Fresno hospital in critical condition.
Officers say they did not receive any shooting calls in the area, much to their surprise.
"We don't know when this occurred, other than it probably occurred recently based on our victim's injuries," said Fresno Police Lt. Israel Reyes.
It's not believed the injury was self-inflicted because police say the car was struck once by gunfire.