Mexico City, Jan 10 (EFE).– Sinaloa cartel kingpin Joaquin “El Chapo” (Shorty) Guzman’s sons, Ivan Archivaldo and Alfredo Guzman, confirmed in Twitter posts on Sunday the authenticity of the photograph showing their father meeting with actor Sean Penn, who interviewed the Mexican drug lord for Rolling Stone magazine.

“Short, but always with the best posture,” Alfredo said in a post intended to serve as a caption for the photograph showing Penn and Chapo shaking hands and facing the camera.

The photograph, which confirms that Penn and Guzman met, was retweeted by Alfredo’s brother, Ivan.

Rolling Stone published an article, titled “El Chapo Speaks,” on Saturday, describing “a secret visit with the most wanted man in the world” in which Mexican actress Kate del Castillo also participated. There were plans of a potential biopic about the drug lord’s tumultuous life.

The interview, conducted in October while Guzman was on the run, helped open a new line of investigation and eventually led the security forces to the drug lord, who escaped from a maximum-security prison outside Mexico City on July 11.

Guzman’s location was tracked to a home in Los Mochis, a Pacific coast city in his native state of Sinaloa, and marines raided the residence early Friday, an operation in which five of the kingpin’s men were killed and one marine was wounded.

The drug lord escaped through sewers along with his security chief, Jorge Ivan Gastelum Avila, another of the Mexican government’s most-wanted fugitives, but both men were apprehended after they tried to flee in a car.

The drug lord had earlier busted out of a Mexican prison in 2001 and evaded authorities for more than 13 years before being recaptured on Feb. 22, 2014, in the Pacific resort city of Mazatlan.

Guzman’s sons used Twitter to express support for their father and threaten the government.

“They don’t know either what they did or the kind of fight they got themselves into,” Ivan Guzman said.

Ivan also criticized President Enrique Peña Nieto, calling him “an ingrate.”

“They see my father like a trophy when the trophy should be putting an end to the extortionist kidnappers,” Ivan said.

Alfredo, for his part, said the government “will get to know the Guzmans pretty soon.”

Chapo Guzman is back behind bars at the Altiplano maximum-security prison, which is being guarded by Federal Police officers, state police and army troops to prevent another escape, an EFE reporter confirmed.

Security has been tightened both inside and outside the prison, a Federal Police spokesman told EFE.

The National Security Commission said Sunday that security around the Altiplano prison “comply fully with international protocols in this area.” EFE