SAN FRANCISCO (AP) — A multi-year racketeering investigation of a San Francisco Chinatown group that led to the conviction of a California state senator escalated Friday when federal prosecutors charged a key defendant with murder.

Raymond “Shrimp Boy” Chow pleaded not guilty to murder in aid of racketeering, which carries a potential sentence of death, and conspiracy to commit murder in aid of racketeering during a brief court appearance.

Chow is accused of arranging the 2006 shooting death of Allen Leung, who preceded Chow as leader of the Chinese fraternal group Ghee Kung Tong.

The FBI alleges Ghee Kung Tong was a racketeering enterprise, and that undercover agents laundered $2.6 million in cash from illegal bookmaking through the organization. The investigation of the Ghee Kung Tong also led to the arrest of state Sen. Leland Yee, who pleaded guilty to racketeering in July.

Chow is also accused of soliciting the murder of Jim Tat Kong, a suspected organized crime figure.

Prosecutors have said two of Chow’s former co-defendants, Kongphet Chanthavong and Andy Li, will implicate Chow in the murder plots.

Chanthavong will testify that Chow was angry with Leung because he wouldn’t loan Chow money from the Tong and wanted to replace him so he could control the organization, prosecutors say in court documents.

Chow ordered the hit outside an Oakland bar, though Chanthavong said he did not immediately know the target was Leung, prosecutors say.

Chow accused Kong of trying to intimidate people in another group, according to prosecutors. Kong was found shot to death in 2013.

Chow’s attorney, Curtis Briggs, has said his client had nothing to do with the slayings and called the allegations ridiculous.

Chow previously pleaded not guilty to racketeering and money laundering and is scheduled to go on trial next month. A judge on Thursday decided to exclude the capital murder charge from Chow’s upcoming trial, meaning it would have to be tried separately.

Prosecutors wanted to delay Chow’s trial to allow the U.S. Justice Department to determine whether to seek the death penalty against him in Leung’s killing, but the judge denied that request.