The latest developments in the escape of Mexican drug lord Joaquin “El Chapo” Guzman involve newly-released surveillance footage revealing a banging noise coming from inside his maximum security cell at the Altiplano prison just moments before he escaped.

Banging heard in El Chapo’s cell before escape http://t.co/tsLzizHMLD pic.twitter.com/xOUfHtQnbr

— ABC7 Eyewitness News (@ABC7) October 15, 2015

The video, which was previously released to the public by the Mexican government, initially shows El Chapo tucked under a blanket on his bed, watching TV.  

Mexican media company Televisa shared the audio recording to match the video, and it reveals a banging sound that persists for almost four minutes before El Chapo gets up and heads to the shower area of his cell. Approximately two minutes later, after pacing back and forth from his the shower and his bed, El Chapo disappears.

Mexican and U.S. law enforcement immediately joined forces in capturing El Chapo. U.S. drug agents were reported to have intercepted cell phone communications between members of the Sinaloa drug cartel in order to get information on his whereabouts.  They suspect that the fugitive drug lord is hiding at one of his ranches in the Mexican Sierra Madre mountains.

Raid of Mexican ranch for “El Chapo” turns up empty: http://t.co/GRps1bGVJ4 pic.twitter.com/vG022ho8yK — CBS Evening News (@CBSEveningNews) October 15, 2015

However, Mexican Marines returned empty-handed after launching a raid in the said ranch.

According to sources, all that was found in the ranch were clothing, cell phones, and other items that are believed to belong to El Chapo.

Upon inspection of the escape tunnel by Mexican authorities, it was discovered that it measured almost one mile and connected the two-by-two foot hole in the shower floor all the way to an empty construction site south of the prison.

Infographic shows the tools that may have been used to construct El Chapo’s escape tunnel http://t.co/EfbvI2csfZ pic.twitter.com/h3Iw5lAPXC

— BI Military&Defense (@BI_Defense) October 12, 2015

Hailed as the “Osama bin Laden of drug trafficking,” El Chapo remains the most wanted man in Mexico and is now also public enemy number one in Chicago. Chicago crime commission executive director Joseph Mays attributes his city’s numerous drug-related violence to El Chapo.