SAN JOSE -- A 20-year-old San Jose transient has been charged with manslaughter in an assault on another homeless man who spent weeks fighting for his life before he died from his injuries earlier this month, according to the San Jose Police Department.

Robert Jaime, who had been in jail on an assault charge in connection with an attack on Myung Shin Oh, 46, now faces an involuntary manslaughter count after Oh died July 6.

Police say Oh was assaulted at 1 p.m. June 9 underneath the Highway 87 overpass between Santa Clara and San Fernando streets. The Santa Clara County Medical Examiner-Coroner's Office said Oh died of head trauma and classified his death as a homicide.

It was the city's 29th homicide of the year by declaration, though chronologically it is the 26th based on when he died.

Officer Albert Morales said witnesses and physical evidence led investigators to identify Jaime as a suspect in the attack on Oh. He was arrested July 2 and was already in custody when the manslaughter charge was filed Wednesday.

Morales said detectives do not believe that the suspect and victim knew each other and do not know what may have motivated the attack.

The area where Oh was beaten is home to a number of transients, and while some had seen Oh before, several of the homeless said they didn't know anything about him.

James Wilcox, 55, said he was sleeping at a park across the street from the overpass when Oh was attacked.

"People say he was going through somebody's stuff and they caught him," Wilcox said.

Oh had been on life support at Santa Clara Valley Medical Center since the beating, which left him comatose. Hospital staff said late last month that he never regained consciousness and was not responding to stimuli.

Police had trouble tracking down friends or relatives of Oh, who was identified through his fingerprints. His family was eventually tracked to Seoul, South Korea, according to the coroner's office.

Anyone with information about the assault is asked to call San Jose police at 408-277-4161. Anonymous tips can be made to Silicon Valley Crime Stoppers at 408-947-7867 or at svcrimestoppers.org.

Staff writer Eric Kurhi contributed to this report. Contact Robert Salonga at 408-920-5002. Follow him at Twitter.com/robertsalonga.