A court in Mexico has begun formal proceedings against four criminal justice workers for their alleged role in aiding the escape of notorious Mexican drug lord Joaquin “El Chapo” Guzman from a maximum-security prison.

Two of the men were prison employees charged were tasked with monitoring El Chapo’s cell via video surveillance, while the other two worked for the Mexican intelligence service.

According to Yahoo News a federal judge stated that the workers failed to follow “protocol and norms” and did not alert higher-ups to the incipient jailbreak in a timely fashion. This isn’t the first time workers have been indicted in this case, as three other workers were charged several weeks prior for aiding Guzman’s daring escape in July.

Guzman, who had been locked up in the Altipano maximum-security prion outside Mexico City following his arrest 17 months ago, escaped out of a 1.5-kilometer (one-mile) tunnel dug under his private shower in the prison and has vanished, but not without a trace.

CNN reported that on August 31, a Twitter account believed to belong to El Chapo’s son, Alfredo Guzman, tweeted out a photo of the 29-year-old flanked by two unidentified men whose faces were obscured by emoticons. Accompanying the photo was a short post that said: “Satisfied here, you already know with whom.”

The tweet’s location showed Costa Rica, although it remains unclear whether the location tag was purposely or inadvertently left on, nor is it clear if the Costa Rica referred to in the tweet was referring to the Central American country or the Mexican town in Sinaloa.

Aside from drawing significant international attention, El Chapo’s escape has dealt a crushing blow to the Mexican government, as President Enrique Pena Nieto had pointed to El Chapo’s arrest last year as its biggest victory yet in his administration’s ongoing war on drugs.

This is not the first time that Guzman, 58, has eluded federal authorities and high-security prison. In 2001, while detained in prison, El Chapo reportedly stowed away on a laundry cart and was rolled out of the front door, where he evaded capture until last year.

Currently, the Mexican government is offered a reward up to 60 million pesos ($3.8 million) for information leading to Guzman’s whereabouts and arrest, while the U.S. government has announced a similar reward up to $5 million for information leading to El Chapo’s capture.

Image Credit: Ronaldo Schedmidt/AFP/Getty Images