Updated

Jurors in the murder and racketeering trial of a key defendant in a San Francisco Chinatown crime probe are set to hear another day of testimony from one of the prosecution's main witnesses — an FBI agent who posed as an East Coast mobster interested in laundering proceeds from illegal sports betting and marijuana cultivation.

The agent, who is testifying under the pseudonym "David Jordan" to protect his identity, is scheduled to take the stand for a third day on Thursday after testifying that Raymond "Shrimp Boy" Chow tried to distance himself from criminal activity.

Chow told the agent he did not want to know about the crimes being committed, but then accepted thousands of dollars from the agent after the introductions and said, "'I'm not involved in any criminal activity anymore, but I know and approve of what's going on in the streets,'" the agent said.

Prosecutors say Chow took over a Chinese fraternal group with criminal ties after having its previous leader killed and ran a racketeering enterprise that engaged in drug trafficking, money laundering and the sale of stolen cigarettes and alcohol.

The investigation previously led to the conviction of a state senator.

Chow's attorneys say the agent instigated the crimes for which people were later arrested and forced money on Chow, often when he was drunk. They say Chow — a former gang leader — was reformed and wanted nothing to do with crime. They will have an opportunity to cross-examine the agent.

The agent described an elaborate undercover operation in which money laundering transactions were referred to in code as "coffee." He had another undercover agent pose as his girlfriend.

The agent spent hours with Chow and people connected to him at fancy restaurants and nightclubs, recording many of their conversations as he built a case that would ultimately lead to the charges against Chow and more than two dozen others and the conviction of former state Sen. Leland Yee, who pleaded guilty to racketeering in July.