MEXICO CITY, Sept 18, 2022 (BSS/AFP) - Mexico will "insist" the US extradite the alleged mastermind behind the murder of journalist Javier Valdez, its attorney general's office said on Saturday after the suspect was released from an American prison.

Damaso Lopez Serrano, a drug trafficker known as "Minilic", is accused of ordering the May 2017 murder of Valdez, an award-winning journalist and AFP contributor who covered the drug trade.

Lopez Serrano was released on Friday, according to the US Federal Bureau of Prisons.

He surrendered to the US Drug Enforcement Agency in July 2017 and cooperated with authorities in exchange for a reduced sentence.

The attorney general's office said on Saturday it would now "insist on his extradition to Mexico", which was first requested in 2020.

The office added that the US Department of Justice had informed it verbally that Lopez Serrano was still being "prosecuted for other crimes", and for that reason the extradition could not yet be completed.

Valdez's widow, Griselda Triana, said she was outraged at the US release of Lopez Serrano.

"Minilic, who paid 100,000 pesos to kill him (Valdez), will now work for the US government," she said in a Facebook post.

"The United States protects murderers of journalists! Let's not allow it!"

Mexico has jailed two people in connection to Valdez's murder -- Heriberto Picos, who was sentenced to 14 years in prison in 2020, and Juan Francisco Picos, who was sentenced to 32 years in prison in 2021.

Valdez was shot and killed in his car on May 15, 2017 in the northwestern city of Culiacan near the offices of Riodoce, the weekly newspaper that he helped to found.