Mexican authorities are considering bringing charges against those who handed over the country’s most-wanted drug lord and co-founder of the Sinaloa Cartel, Ismael "El Mayo" Zambada Garcia, to the U.S. last month.

On July 25, U.S. officials announced that Zambada Garcia was taken into custody in El Paso, Texas, alongside Joaquín Guzmán López, the son of the cartel's other co-founder, Joaquin "El Chapo" Guzman.

Guzmán López flew to the U.S. to turn himself in to U.S. authorities, but abducted Zambada Garcia before leaving Mexico, forcing him onto the plane, officials said.

Instead of thanking the U.S. for apprehending Zambada Garcia — who is responsible for leading a cartel that has terrorized and spread violence across Mexico for decades — Mexican prosecutors are considering treason charges against Guzmán López and anyone else involved in the abduction.

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The Mexican attorney general’s office announced on Sunday it had opened a criminal investigation "for the possible crimes of illegal flight, illicit use of airports, immigration and customs violations, kidnapping, treason, and any other crimes that may apply."

The U.S. was offering a $15 million reward for the capture of Zambada Garcia, and Mexico’s response to the apprehension is based on the country’s penal code that lays out prison sentences of up to 40 years in prison for treason, the Associated Press reported.

The penal code article not only includes traditional definitions of treason like attacking Mexico on behalf of a foreign power or serving a foreign army, but also states treason is committed by anyone who illegally abducts "a person in Mexico in order to hand them over to authorities of another country."

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The clause was added in response to the abduction of Mexican doctor Humberto Machaín, who was kidnapped in Mexico in 1990 and handed over to the U.S. Machaín was wanted for allegedly participating in the 1985 torture and murder of Drug Enforcement Administration (DEA) agent Kiki Camarena.

President Andrés Manuel López Obrador reportedly said Monday he questioned the U.S. policy of detaining drug cartel leaders, asking, "Why don’t they change that policy?"

Zambada Garcia’s lawyer, over the weekend, released a letter from his client, claiming he was ambushed and kidnapped when he believed he was going to meet with the governor of Sinaloa. Instead, Zambada Garcia claimed, he was taken against his will to the U.S.

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Zambada Garcia also reportedly claimed in the letter that Guzmán López asked him to attend a meeting on July 25 with local politicians, but instead, he was led to a room and knocked down before a hood was placed over his head. Zambada Garcia said he was handcuffed, driven to a landing strip in a pickup truck, and forced into a private plane that delivered him to U.S. soil.

In the letter, he raised questions about the links between Sinaloa politicians and drug traffickers, though Gov. Richa Moya denies any links to criminals and claimed he was not in Sinaloa on the day of the abduction. Instead, Moya reportedly said he was in Los Angeles.

The attorney general’s office has taken the case over from Sinaloa state prosecutors.

Zambada Garcia has been charged in numerous U.S. cases, including one filed in February in the Eastern District of New York accusing him of conspiring to manufacture and distribute fentanyl. Prosecutors said he led "one of the most violent and powerful drug trafficking organizations in the world."

Now that Zambada Garcia is behind bars, experts say many powerful people in Mexico will be concerned that in a bid for a more comfortable deal, he could cooperate with U.S. authorities and accuse them of collaborating with the cartels.

Fox News’ Adam Shaw and The Associated Press contributed to this report.