A frequent shopper told Eyewitness News the victim is the store's owner.
Authorities responded to the 98 Cents Store in the 5000 block of Hollywood Boulevard around noon Tuesday and found Khotsuryan with gunshot wounds. He was declared dead at the scene.
Police said the suspect was seen wearing a gray hooded sweatshirt, a white shirt and a white hospital mask. He has not been found.
The victim appeared to have been alone in the store at the time, and there was no video surveillance footage of the store interior, LAPD Sgt. David Armas said.
A motive for the shooting was not immediately determined.