A man who allegedly confessed to working as a hitman for the Gulf Cartel pleaded not guilty to federal terrorism charges, court records show.

Jose Flores-Flores, a Mexican national from Reynosa, Tamaulipas, waived an arraignment on Monday, automatically entering a plea of not guilty. 

The 21-year-old man was indicted on Sept. 15 on charges of providing material support to terrorists and illegal entry. Federal officials announced the terrorism charges in a press conference held the following day in McAllen. 

Federal officials in McAllen announce terrorism charges against alleged cartel member from Reynosa

Flores-Flores was apprehended on July 10 near Mission. A federal grand jury in the Southern District of Texas has since indicted him on multiple charges after the Gulf Cartel became a federally designated terrorist organization.

Federal officials said those charges would not have been possible without President Donald Trump designating the Gulf Cartel as a foreign terrorist organization.

According to the indictment, agents found "disturbing" videos and images on his phone that showed Flores-Flores dismembering a body with a handsaw. Other images showed piles of dismembered human remains and a burn barrel on fire.

Data tied to the files showed they were created on June 26 near Reynosa. Flores-Flores waived his rights and spoke with agents, telling them he worked as a barber and a hitman for the Gulf Cartel for about a year “doing bad things on that side.”

According to the indictment, Flores-Flores received names or photographs of individuals targeted for kidnapping. He allegedly kidnapped those individuals and delivered them to higher-ranking cartel members.

“As a hitman, he stated that part of his job for the CDG was ‘to protect his area,’ ensuring ‘no one to be stealing, committing extortion’ and 'for no one to be, more than anything, kidnapping people and all,'” the indictment states.

When agents showed him the video, Flores-Flores admitted it was him in the footage, according to the indictment. He said the victims had violated Gulf Cartel rules by extorting people and kidnapping others without the cartel's knowledge. He said he sawed off the victims' arms to make the bodies easier to burn.

Records showed Flores-Flores had previously been convicted of entering the United States illegally.

Flores-Flores remains in federal custody. If convicted on the new charges, Flores-Flores faces up to 20 years in federal prison and a possible fine of up to $250,000. 

A new court date for Flores-Flores was not set as of Tuesday.