NEW YORK (Reuters) – Joaquin “El Chapo” Guzman was “the boss” of Mexico’s Sinaloa Cartel, a witness told jurors in the accused Mexican drug lord’s trial in Brooklyn federal court on Monday, contradicting the claim by Guzman’s lawyers that his dominance of the drug trade was a myth.

Miguel Angel Martinez, who described himself as a former manager in the cartel, took the witness stand on the sixth day of Guzman’s drug trafficking trial, testifying under an agreement to cooperate with prosecutors. For his safety, court sketch artists were ordered not to draw an accurate likeness of him.

“I knew that he was the boss,” Martinez said when a prosecutor, Assistant U.S. Attorney Michael Robotti, asked him about Guzman’s role in the organization. “Since I met him, he would give all of us orders.”

Guzman, 61, was extradited from Mexico in January 2017 and faces life in prison if convicted. His lawyers are seeking to prove that another drug lord, Ismael “El Mayo” Zambada, actually ran the cartel and used Guzman as a scapegoat.

Martinez said he began working for Guzman as a pilot and as a guide to other pilots on drug flights in 1987. He said one of the pilots he assisted that year, on a flight carrying 170 kilograms (375 lbs) of cocaine, claimed he had flown in the U.S. Navy.

Martinez said he was soon relieved of his pilot duties after damaging a propeller in a botched landing with Guzman on board. Guzman, he recalled, told him he was a “really bad pilot” and sent him instead to Mexico City to open an office for the cartel.

Posing as attorneys, Martinez said, he and others at the office directed bribes to government officials so the cartel could operate undisturbed. The beneficiaries included a high-ranking police official, Guillermo Calderoni, who fed Guzman information about law enforcement activities “every day,” Martinez said.

Martinez said he and Guzman became close, and that in 1989, Guzman became the godfather to Martinez’s newborn son.

Martinez said he often talked by radio to the Colombian cartel pilots who would bring cocaine to Mexico, using code words to avoid detection. Drug shipments, he explained, were “parties.” “Wine” meant jet fuel, and “girls” were planes.

In the 1990s, Martinez said, U.S. authorities became more capable of intercepting planes, and Guzman and his Colombian suppliers largely switched to using fishing and merchant ships.

Martinez is expected to continue testifying on Tuesday.