A member of the Asian Boyz street gang was sentenced Monday to 15 years in prison for a 2007 kidnapping in which a potential witness was later murdered.

Pongsony Patrick Kahoone, 22, admitted being among four men who kidnapped Terry Au, a one-time drug dealer for the gang who was abducted when he tried to quit.

Au's brother, Vutha Au, then 24, was shot to death in 2008 at Blind Beach on the Sonoma Coast as he was preparing to testify in the attack.

Preston Kahoone, 23, Tyrone Tay, 28, David Prak, 21, Sarith Prak, 23 and Quentin Russel, 26, Boonlak Chanpheng, all of Santa Rosa, are charged with Au's murder March 2, 2008 and could go to trial this fall.

Meanwhile, defendants in the underlying kidnapping are getting sent to prison.

Prosecutors said the accused abducted Au from him from his home Oct. 1, 2007, burned him with cigarettes and threatened to cut off his fingers unless he paid them $5,000.

Pongsony Patrick Kahoone, 22, pleaded to a single count of kidnapping with a gang enhancement. His brother, Perry Kahoone, 26, will get 18 years at his sentencing on July 19. A third defendant, Boonlak Phanchanh, 23, is to be sentenced Wednesday to 13 years in prison.