A Mexican government official said Thursday that the country is investigating the leak of the plans for the maximum-security prison to Joaquin "El Chapo" Guzman’s aides, which helped the drug cartel leader escape in dramatic fashion on Saturday night. The government has reportedly fired the director of the prison after Guzman's escape amid criticism of President Enrique Peña Nieto’s administration.

"Regarding the plans, it's part of the investigation that we're doing ... who participated, who handed them over, when they got them," Miguel Angel Osorio Chong, the country’s interior minister, said, at a news conference Thursday, according to Reuters. "Our objectives are clear, recapture this criminal and punish each of his accomplices," Chong said, adding: "It won't be easy."

According to a civil engineer working for the government on the investigation, cited by the New York Times, Guzman may have spent at least $1 million on his escape.

Guzman’s escape route was reportedly a tunnel that ran from a seemingly abandoned property near the Altiplano prison to a spot below the shower in his cell. Video footage released by Mexico shows Guzman pacing in his cell and changing his shoes just minutes before he disappears behind a wall that partly covers the shower. More than 30 feet below, the earth was dug out by Guzman’s workers who used a motorcycle on rails to clear out over four tons of mud they displaced in building the tunnel. The workers also equipped the tunnel with lighting and ventilation shafts to help Guzman navigate, according to reports.

“If they had missed the calculation by one degree, or made one little mistake, Chapo would have emerged in someone’s kitchen” the civil engineer said, according to the Times.

The latest escape was the second one for Guzman in 15 years. Guzman, who was first arrested in 1993, escaped in 2001 by bribing police officials. He was captured again last February in northwestern Mexico, Reuters reported.

The escape has triggered a massive manhunt and a “maximum alert” to about 8,200 police officers in every state. About 100,000 leaflets with Guzman’s picture have so far been distributed to highway toll booths while officials have set up 101 checkpoints on main highways across the country, according to reports. The government has also offered a $3.8 million reward for Guzman's capture.