The 19-year-old Santa Rosa man accused in a fatal stabbing on the grounds of Kawana Elementary School is the suspected shooter in a year-old Contra Costa County slaying that claimed the life of a bass guitarist who toured with the hip-hop singer Lauryn Hill, the CHP said Thursday.

Raul Vega is charged with Saturday's killing of Juan Carlos Angel-Esparza, 20, in a gang-related fight on the campus as well as the Jan. 12, 2010 drive-by shooting of musician Dewey Tucker, 24, who authorities said he had mistaken for a gang rival.

Along with his three co-defendants in the Tucker slaying, Vega pleaded not guilty Thursday to both killings and other charges including conspiracy to commit murder, shooting into an occupied vehicle and participation in a gang.

"Based on evidence and interviews we are very confident Mr. Vega is the shooter in the Tucker case," said Sgt. Trent Cross, spokesman for the CHP's Golden Gate division.

Cross said CHP investigators were zeroing in on Vega when he was arrested by Santa Rosa police in the school slaying. Cross would not describe the evidence linking Vega to the Tucker case or say how investigators became aware of the other three defendants.

"The timing was strange," Cross said. "We were at the tail end of our investigation and were going to seek him (Vega) out. He happened to get arrested in another incident."

By agreement between Contra Costa and Sonoma county prosecutors, the case will be tried in Sonoma County, Cross said.

Prosecutor Bob Waner also would not disclose details of the case or how the two killings are connected in advance of a preliminary hearing set for Jan. 21.

"That's going to become very clear at the prelim," Waner said.

The other defendants in the Tucker case are Christopher Mancinas, 29, Hector Barragan, 28 and Javier Ivan Carreon-Lopez, 20, all of Santa Rosa.

Like Vega, they face murder, conspiracy and gang charges in Tucker's death along with special circumstances that could lead to life in prison or the death penalty.

According to charging documents, the four had received word from deputies of threats against Barragan made by a rival gang member and planned to retaliate.

They drove to Contra Costa County and staked out the man they thought was the rival. It turned out it was Tucker. As he drove on Interstate 80 near the town of Crockett, the fired on him, striking him in the dead. He died at the scene.

They returned to Santa Rosa and gave the gun to a gang associate. It has since been recovered by detectives, according to the criminal complaint.

Each man was assigned a court-appointed lawyer on Thursday. Speculation that the two murders could be tried separately could not be confirmed.