Joaquin Guzman Lopez, the son of convicted Mexican drug kingpin Joaquin “El Chapo” Guzman, has pleaded not guilty to drug trafficking and other charges in a United States court. Guzman Lopez, dressed in an orange jumpsuit, stood in a Chicago courtroom on Tuesday with his feet shackled as federal prosecutors detailed a five-count indictment that also includes weapons charges. US District Judge Sharon Johnson Coleman ordered him detained pending trial. The judge did not set a trial date and scheduled the next court date in the case for September 30. The hearing came just days after US authorities arrested Guzman Lopez and Ismael “El Mayo” Zambada, a longtime member of Mexico’s Sinaloa cartel, in the El Paso, Texas area last week, according to the US Department of Justice. Many of the details of the arrest operation remain murky, however. Last week, US officials familiar with the situation said Guzman Lopez duped Zambada into boarding a propeller plane in Mexico by saying they were going to scope out real estate in the country’s north. Instead, the plane brought both men to the US, where Guzman Lopez had planned to surrender, but Zambada had not. Zambada’s lawyer, Frank Perez, disputed the version of events offered by US officials. Perez said that Guzman Lopez “forcibly kidnapped” Zambada and brought him to the US against his will. Zambada pleaded not guilty to drug charges last week in El Paso federal court. Mexico has opened an investigation into the events leading to the two men’s arrest. Their capture fuelled theories about how US authorities pulled it off and prompted Mexican President Andres Manuel Lopez Obrador to take the unusual step of issuing a public appeal to drug cartels not to fight each other. “Those who are engaged in these illegal activities know they resolve nothing with confrontations,” Lopez Obrador said on Monday, adding “They would go out and risk the lives of other human beings, and why make families suffer?” There were no immediate reports of increased violence over the weekend. But the Sinaloa cartel has been riven for years by fighting between followers of Zambada and rivals who follow El Chapo’s sons, known collectively as Los Chapitos, or “The Little Chapos”. Their father was convicted of drug charges in New York in 2019 and is serving a life sentence in a maximum security prison. US Drug Enforcement Administration chief Anne Milgram said Zambada’s arrest “strikes at the heart of the cartel that is responsible for the majority of drugs, including fentanyl and methamphetamine, killing Americans from coast to coast”.