A hitman for infamous kingpin Joaquin El Chapo Guzman had a "murder room" that was sound-proofed and included a "drainage outlet," a witness said Monday in the El Chapo trial, the New York Post reported. "He took me once to a house, where the floor was just white, tiled," the witness, Edgar Galvan, reportedly said of Antonio Marrufo. "That's where he killed people."

Galvan met Marrufo -- known as Jaguar -- after he divorced in 2003 and rented a home south of the Mexican border in Ciudad Juárez, which is right next to El Paso, Texas, The New York Times reported. It was then that Galvan said he became "party friends" with Jaguar, who was tasked with "cleansing" Juárez of its rivals.

He said he started working with Jaguar several years after they met. He moved firearms and received marijuana and Mexican cocaine shipments at safe houses in El Paso, the Times reported.

Get Breaking News Delivered to Your Inbox

In 2011, Galvan was arrested. He told jurors he has since served eight years of a 24-year sentence, the Post reported, while Jaguar is in jail in Mexico.

Meanwhile in the ongoing trial, which began in mid-November, a former Mexican drug trafficker and heir to the Sinaloa cartel wrapped up his testimony. Vicente Zambada, the 43-year-old son of Guzman's partner, Ismael "El Mayo" Zambada, had testified against Guzman, providing intimate details of the accused Mexican drug lord's life. He described the rampant violence and corruption that accompanied Guzman's rise to power atop the Sinaloa cartel.

Guzman is facing conspiracy charges at the trial in federal court in Brooklyn. He was sent to the U.S. to face trial in 2017 after making a fortune running the cartel and breaking out of Mexican jails two times.

Last week, jurors saw evidence that Guzman knew how to live it up even while his life was in danger. Prosecutors introduced photos Friday of an armed Guzman dancing with an unidentified woman. One photo shows that he was carrying a diamond-encrusted pistol to protect himself.