Sonoma County prosecutors said Friday they will not seek the death penalty against four members of a criminal gang accused of killing the brother of a trial witness near Jenner.

The decision in the 2-1/2-year-old slaying reduces the maximum possible sentence for those accused of killing Vutha Au, 24, of Santa Rosa, to life in prison without parole.

District Attorney Stephan Passalacqua said the lengthy process included waiting on scientific evidence and meetings with the victim's family.

He found that the case, which alleges the special circumstances of kidnapping and committing a murder to benefit a gang, didn't qualify as among "the worst of the worst" cases that should be punishable by death.

"This is a very difficult matter for the family," Passalacqua said. "We consulted with them and listened to their input. The ultimate decision is the one I reached."

Now the defendants, suspected shooter Quentin Russell, 27, Preston Khaoone, 24, and brothers David, 22, and Sarith Prak, 24, all of Santa Rosa, will head to trial, probably sometime next year.

With the death penalty off the table, the county will no longer be charged for a second court-appointed attorney for each of the four men.

"I don't know why it took them more than two years to figure it out," said Russell's attorney, Martin Woods.

Under a defense motion Friday, two other defendants, Boonlack Chanpheng, 29, also of Santa Rosa and Tyrone Tay, 28 of Suisun City, will be tried separately on Jan. 10. Their lawyers argued the two men were not at the scene of the crime or had no knowledge of criminal plans.

In granting the motion, Judge Ken Gnoss acknowledged their cases were different. He said they were "not present during the execution" of Au.

Last year, prosecutors announced they would not seek the death penalty against Chanpheng and Tay.

Prosecutors allege the six men killed Au to intimidate his brother, Terry Au, 23, who was to testify that he was kidnapped and beaten by a group of drug dealers including one of the defendant's brothers.

On March 2, 2008, prosecutors say, the defendants abducted Vutha Au and drove him to Blind Beach near Goat Rock, where he was shot nine times. His body was found in a parking lot.