Two young men were drinking rum on a downtown Oakland street, angry at life and looking for someone to punch, before they happened on a San Francisco man who had come to town with his father to shop, prosecutors said Thursday.

Lavonte Drummer and Dominic Davis, both 18 and Oakland residents, were charged with murder in connection with what authorities called a random, unprovoked attack on the son on April 16 and the subsequent fatal beating of his father, Tian Sheng Yu, 59, of San Francisco.

Although there has been speculation that the attack was motivated in part by race - Drummer and Davis are African American, and the elder Yu was a Chinese immigrant - Chief Deputy District Attorney Tom Rogers said the suspects could have sucker-punched anyone who crossed their path on Telegraph Avenue near the Fox Theater. He said there was no evidence the attack was a hate crime.

Rogers painted a picture of the defendants as thugs with juvenile arrest records who were killing time on a Friday afternoon by sharing a bottle of Bacardi rum and grousing about their lives.

Drummer in particular, he said, was "frustrated by personal circumstances."

"Drummer stated that he had anger and frustration over his life and planned on hitting someone," police wrote in a statement that outlined grounds for the arrests.

Shopping for coins

It was random bad luck, Rogers said, that brought Yu and his son, Jin Cheng Yu, 27, into contact with the two as they were on their way to shop for coins at a jewelry store.

The son was the first victim, being sucker-punched by Drummer as the elder Yu was parking his car, Rogers said. Tian Sheng Yu approached the two men and, in Mandarin, demanded an explanation.

He "gestured to both suspects with his finger, but did not touch either suspect," the police statement said.

Video of the attack shows Drummer punching the elder Yu with his right hand, Rogers said. Davis then hit him with a left hook, authorities said.

Tian Sheng Yu "appeared dazed for just an instant, and fell straight backward and hit his head" on the concrete, Rogers said.

Son steps in

Jin Cheng Yu moved in and was punched by both attackers. The younger Yu returned punches, and both he and Drummer fell to the sidewalk, authorities said.

Witnesses then chased the attackers away.

Tian Sheng Yu never regained consciousness and died Tuesday of a skull fracture and a brain injury.

A subsequent outpouring of tips, including some from people who knew the suspects and recognized them from a video released by police, led to the men's arrests, investigators said.

Drummer and Davis appeared before Judge Robert McGuiness of Alameda County Superior Court but did not enter a plea. They are being held without bail.

Among those attending Thursday's hearing were Police Chief Anthony Batts, Jin Cheng Yu and his mother, Zhi Rui Wang, 56.

Oakland Chinatown organizer Carl Chan, speaking on the family's behalf, said they were saddened by their loss and that their "hearts go out to the families of the two young men."

"True justice is no more violence," Chan said.

In deciding against filing hate crime charges, prosecutors noted that the men's criminal histories did not appear to include racial overtones.

Drummer has a felony assault conviction as a juvenile for punching a 55-year-old African American man from behind at an Oakland convenience store in September 2009. The victim hit his head on the pavement, lost consciousness and had to have seven stitches, Rogers said.

Both Davis and Drummer were arrested in April 2007 for allegedly trying to rob a 31-year-old white man in Berkeley. They were released to their parents because charges were never filed.