Ostrem was nonchalant and appeared to be firing randomly with a handgun at people near the cash registers at the front of the Walmart, police said.
Richland County deputies are searching for a suspect who allegedly stole a camera system from Wal-Mart then struck an employee with the box as he was leaving the store.
The incident occurred Thursday at 10060 Two Notch Road.
Ostrem was forced to sit tight at a traffic light as a SWAT team and plainclothes officers descended on him.
Upon his arrest, bystanders shouted to the officers, "Good job, guys!
It also said all of its employees were accounted for and uninjured.