A $20,000 reward was offered Wednesday for information leading to the arrest of the gunman who shot and killed the owner of a Quiznos sandwich shop during a robbery in San Dimas, sheriff’s officials said.

Pravin Patel, 62, was shot in the chest after a robbery at a Quiznos in the 1000 block of West Arrow Highway (map) around 3:25 p.m. on June 2, said Sgt. Rebecca Rodriguez of the Los Angeles County Sheriff’s Department.

“The employee gave over the money and he followed the suspect outside of the location. A struggle ensued in front of the store and the suspect shot the victim,” Rodriguez said.

A woman who ran a business next door rushed to Patel’s aid and called 911.

“It’s really heartbreaking,” Kelly Strong said last week. “It was totally senseless.”

Patel’s niece said the shooting did not need to happen.

“Whoever did this took away a life that never should have been taken away this early, and should never have been taken away in this manner,” said Risha Patel, also speaking last week.

Patel and his wife were the owners of the restaurant, a family spokesman confirmed Wednesday, when a sketch of the shooter was released at an afternoon news conference