CHICAGO (AP) — Ovidio Guzmán López,ánLó a son of former Sinaloa cartel leader Joaquin “El Chapo” Guzmán, pleaded not guilty Monday to drug trafficking, money laundering and other charges during his first court appearance since being extradited to the U.S. from Mexico.

Guzmán López was extradited Friday, five months after U.S. prosecutors unsealed sprawling indictments against him and his brothers, known collectively as the “Chapitos.” The indictments laid out how following their father’s extradition and eventual life sentence in the U.S. in 2019, the brothers steered the cartel increasingly into synthetic drugs such as methamphetamine and the powerful opioid fentanyl.

Mexican security forces captured Guzmán López, known as “the Mouse,” in January in Culiacan, capital of Sinaloa state, the cartel’s namesake. His arrest set off violence that left 30 people dead, including 10 military personnel. Mexico’s army used Black Hawk helicopter gunships against the cartel’s truck-mounted .50-caliber machine guns. Cartel gunmen hit two military aircraft, forcing them to land, and sent gunmen to the city’s airport, where military and civilian aircraft were hit by gunfire.

Three years earlier, the government tried to capture him, but aborted the operation after similar violence.

The U.S. indictments against the brothers that were unsealed in April said their goal was to produce huge quantities of fentanyl and sell it at the lowest price. The brothers denied the allegations in a letter.

“We have never produced, manufactured or commercialized fentanyl nor any of its derivatives,” the letter said. “We are victims of persecution and have been made into scapegoats.”

Homeland Security Adviser Liz Sherwood-Randall said in statement Friday that the extradition of Guzmán López “is testament to the significance of the ongoing cooperation between the American and Mexican governments on countering narcotics and other vital challenges.” Sherwood-Randall made multiple visits to Mexico this year to meet with President Andrés Manuel López-Obrador, most recently last month.

López Obrador has described his country as a transit point for fentanyl precursors coming from China and bound for the U.S., despite assertions by the U.S. government and his own military about production in Mexico.