SAN JOSE -- A man suspected of executing a 16-year-old boy at the end of a savage gang beating in June remains in a Seattle-area jail awaiting extradition to join five others in facing murder charges, authorities said.

Juan Godinez Tafolla 19, of San Jose -- who also goes by Juan Tafolla Godinez -- was arrested Oct. 18 in Washington state by the U.S. Marshals Service after eluding capture for more than four months. He is the suspected triggerman in the death of Manuel Urzua, who was killed June 19 in a gang-plagued neighborhood near Virginia Avenue and King Road in East San Jose.

Meanwhile, the District Attorney's Office charged two boys accused of participating in the attack as adults. Usiel Teram Garcia, 15, and Samuel Villano Zamora, 17, were each charged with murder and a gang enhancement.

Also charged with murder and gang enhancements are Tafolla; Jorge Luis Ibarez, 22; and Olsen Garcia Sanchez, 25. All are from San Jose.

Antonio Sanchez, 34, of San Jose, has been charged with being an accessory after the fact, accused of helping the other suspects avoid arrest. He is also charged with a gang enhancement. Prosecutors allege that the defendants are members of a street gang, but other than Tafolla, the degree of their involvement was not immediately known.

The suspects were arrested by the San Jose Police Department's covert response unit between Oct. 8 and Oct. 18, when Tafolla was tracked in Washington. By the earliest estimates, Tafolla will be transported to Santa Clara County jail to join his co-defendants in the next week or so.

Court files related to the killing have been sealed by the Superior Court, owing to an ongoing investigation, Deputy District Attorney Kevin Smith said. He said that other people could be added by the time police finish their work.

"It's possible. It wouldn't surprise me," Smith said.

In the early stages of the case, witnesses told police as many as 10 people might have been involved in the attack.

Police say Urzua got into a confrontation with a group of gang members who attacked and beat him. Authorities say Tafolla thenshot the teen in the back of the head.

Urzua's death in broad daylight rattled the community and capped a string of gang-related killings that spurred San Jose police to institute a summer-long gang crackdown that flooded problem areas with officers and to resurrect a dedicated gang enforcement unit in August. After eight gang killings in the first half the year, the city has recorded one since.

Contact Robert Salonga at 408-920-5002. Follow him at Twitter.com/robertsalonga.