RICHMOND, Calif. -- The killing of a Pizza Hut deliveryman late Monday evening may have been some kind of gang initiation rite since the gunman left the slain man's cell phone, money and pizza behind, according to Richmond police.

Authorities said early Tuesday that they were working on two theories behind the slaying of the deliveryman -- identified as Thanh Thach of Richmond -- on Richmond's violent streets. It may have either been a robbery gone bad or a form of gang initiation.

"The thing that has been brought up is that this might have been a crime committed for a gang member to establish himself as being hard core or to gain status within the gang," Richmond Lt. Mark Gagan told KTVU. "That is one motive that is being looked at… It is extremely disturbing if that is the case."

Gagan said he was not aware of a murder having been committed on the streets for bragging rights, but said touting crimes was a commonly seen behavior.

"We do see people, when they do commit a crime, they tout it," he said. "As if they are brutal and hard core. We see a lot of guys bragging in court or on the street about what they have done."

Police also do not believe Thach was lured to his death. He was on the phone with the person he was trying to deliver the pizza to when he was shot twice.

At 8:58 p.m., police received a report of the shooting from a resident in the 800 block of South 45th Street, Lt. Ron Berry said.

The female caller said that a man had been shot in front of her home. Responding officers found Thach at the reported location and he was pronounced dead at the scene.

Preliminary reports indicated that Thach was attempting to deliver a pizza to an apartment in the 900 block of South 45th Street but could not locate the building.

As he wandered the neighborhood in search of his destination, unknown assailants approached him and attempted to rob him, Berry said.

Thach tried to run away, but was shot twice from behind.

"The address had had pizzas delivered at least five occasions -- it's an address they had been out to before," said Sgt. Mitch Peixoto. "This delivery person had not been out here before. He was lost."

Gagan added that the killing came in a part of the troubled city that was designated as a high-crime area during the city's state of emergency two years ago.

Gagan described Thach as a 38-year-old Cambodia immigrant. He had a 3-year-old and 18-month-old child and had become a U.S. citizen just two months ago.

"He apparently described that as the best day of his life," Gagan said.

Thach, Gagan continued, had been a deliveryman for just a month and was saving money to bring his mother from Cambodia to the U.S.

The homicide was the 34th of the year in Richmond and came three days after three people were gunned down in separate drive-by shootings on the city's violent streets. The East Bay community was ranked as America's ninth most dangerous city in CQ Press' recent annual survey based on FBI crime statistics.

Richmond police were asking anyone with information on the slaying to call (510) 620-6643.