Sgt. Jeff Walker said the victim and suspect agreed to meet behind a Carl's Jr. at Las Tunas Drive and Golden West Avenue at about 3:30 p.m.
The suspect was supposed to sell the victim an iPhone for $500, but when the victim arrived, the suspect pulled out a handgun and stole his money, Walker said.
The suspect was described as an Asian man about 5 feet 9 inches tall, 160 pounds, with black hair and brown eyes. He was last seen wearing a red jacket.