Investigators found 18 shell casings surrounding a gunshot victim found near Jenner in 2008, yet preliminary tests show none of the four men arrested minutes after the killing had gunshot residue on his hands, according to testimony in Sonoma County court Monday.

The revelations came in the first day of a preliminary hearing for six men accused of killing a man who was in the witness relocation program to prevent his testimony in another case.

Quentin Russell, 25, Preston Khaoone, 23, Tyrone Tay, 27, Boonlack Chanpheng, 27, and brothers David, 20, and Sarith Prak, 22, are charged with murder in the shooting death of Vutha Au, 24, in March 2008 in a Blind Beach parking lot near Jenner.

Investigators say Au was killed so he couldn?t testify on behalf of his brother, 22-year-old Terry Au, who was allegedly kidnapped and beaten by a group of drug-dealing gangsters that included two of Khaoone?s brothers.

The men face charges that could trigger a death sentence, but prosecutors haven?t said whether they will seek the death penalty.

Detectives say neither Tay nor Chanpheng were present during the slaying. They said Tay was with the victim before the other four men drove him to the beach parking lot and that Chanpheng helped plan the attack.

Investigators said one of the other four shot Au nine times, killing him at the scene.

A state parks ranger en route to an unrelated disturbance call spotted Au?s body and saw a car driving out of the beach parking lot about 1 a.m. He broadcast the car description and Sonoma County sheriff?s deputies stopped the eastbound car a few minutes later on Highway 116 near Monte Rio.

A 9mm pistol believed to be used in the shooting was found two months later in the Russian River near the Highway 1 bridge.

In court Monday, Sgt. Darin Dougherty said he documented 18 9mm shell casings near Au, circling his body in two large groupings.

?That told me the shooter would have had to reposition at some point,? he said.

He said Au was found face-down with his arms underneath him, clothed all in black but missing his shoes and socks, which were nearby. A pool of blood circled his head and there were three smaller areas of spilled blood a few feet away, Dougherty said.

After the arrests of Russell, Khaoone and the Prak brothers, Dougherty said he took two samples from each of the men?s hands to help determine if they had recently fired a gun.

He said he didn?t have results from the ?scientific? version of the test results, but said preliminary gunshot residue tests came back negative for all four men. Gunshot residue tests can pick up traces of burned or unburned gunpowder and soot created when a gun is fired.

Further testimony was cut short late Monday when defense attorneys raised issues about whether the four defendants who were stopped in the car were read their rights before being asked at gunpoint to incriminate themselves as gang members.

Judge Ken Gnoss will hear further arguments about the issue this morning. Generally, in-custody suspects must be advised of their legal rights before being questioned by police, although there are exceptions.

Following the preliminary hearing, which is expected to continue into next month, Gnoss will determine if there is enough evidence to hold the men over for trial. All six defendants are being held without bail at Sonoma County Jail during the proceedings.

They are charged with murder, being members of the Asian Boyz gang and six enhancements, including three gun allegations. Two of the enhancements are special circumstances that could trigger life-without-parole prison sentences or the death penalty.

Members of the Au family had been relocated under the county?s Witness Relocation and Protection Program after Terry Au testified in court against his alleged attackers, two of whom are brothers of Preston Khaoone. Prosecutors said Vutha Au was going to be a witness in the trial, which was scheduled for last year but has been reset for July.

Authorities said Vutha Au was kidnapped during one of his occasional returns to Santa Rosa.