In February, Joaquin 'El Chapo' Guzman, 62, was found guilty of trafficking $12 billion worth of cocaine, heroin and marijuana during his reign as the Don of the Mexican Sinaloa Cartel

Ever since Joaquin ‘El Chapo’ Guzman was sentenced to life in prison in a New York court in July, the underground tunnels he once used to traffic tonnes of heroin and cocaine across the US-Mexico border have become the center of a new cartel war.

In February, Guzman, 62, was found guilty of trafficking $12 billion worth of cocaine, heroin and marijuana during his reign as the Don of the Mexican Sinaloa Cartel.

For decades the vast criminal empire Guzman built had utilized the underground tunnels to cement the Sinaloa Cartel’s place atop the world’s most notorious crime syndicates.

Guzman went on to dominate the US drug trade in the late 1980’s, following the downfall and eventual demise of Pablo Escobar.

But despite his own arrest and incarceration, Guzman’s tunnels continue to prosper as a profitable and viable passageway to flood the US with drugs.

However, unlike under Chapo’s reign, the Sinaloa Cartel is not the only gang using the tunnels.

For decades the vast criminal empire Guzman built utilized the underground tunnels to cement the Sinaloa’s Cartel’s place atop the world’s most revered crime syndicates, that went on to dominate the US drug trade in the late 1980’s, following the downfall and eventual demise of Pablo Escobar

But despite his his own fall from grace, Guzman’s tunnels continue to prosper as a profitable and viable passageway to flood the US with drugs

However, unlike under Chapo’s reign, the Sinaloa Cartel is not the only gang using the tunnels

Criminal organizations are working both in tandem and in opposition to one another over the lucrative routes.

Duncan Wood, Director of the Wilson Centre’s Mexico Institute, told Daily Star Online: ‘I imagine that at any one time there are between 10 and 50 tunnels operating.

‘Not all of them are going to active operating at the same time but they will be available. The cartels have invested in a lot of time and effort over the years in building these tunnels.

‘They’re picking out the right locations within urban areas, as well as desert, so that they can move the drugs.’

Wood said one of the main advantages of establishing an operation in an urban area is that you build your tunnels within buildings, and have it come out in a building on the other side.

It essentially allows drug traffickers to hide their trade in plain sight, with the urban backdrop shielding it from the view of authorities.

Guzman, who was once lauded as the ‘master of tunnels’, allegedly sent a number of his cartel engineers to Germany to receive specialized training for underground tunnel construction, which would eventually be put to use to build the escape route used by El Chapo to escape from a maximum security prison for a second time

In the case of the long-established Guzman tunnels, some of them are controlled by one cartel but they lease them out to other groups for a hefty bounty. Often, such payment will include splitting the profits made from the sales of drugs shipped across the border

In the case of the long-established Guzman tunnels, some of them are controlled by one cartel but they lease them out to other groups for a hefty bounty.

Often, such payment will include splitting the profits made from the sales of drugs shipped across the border.

‘That cut of the profits is significant because the last mile is the most difficult and most dangerous’ to traverse, Wood explained.

‘I don’t know whether you’ve got different factions controlling different crossings at the border. I’m sure that is the case, but I don’t know where,’ he continued.

Last October, DEA agents shut down an incomplete cross-border tunnel near the city of Jacumba in the state of California less than a mile north of the US-Mexico border.

The underground tunnel was highly innovative, containing solar panels designed to run electrical, lighting and ventilation systems, in addition to having two sump pumps to drain the tunnel of any water that gathered inside.

Typically, depending on the length and complexity, the tunnels can cost anywhere between $1,000,000 and $2,000,000 to construct, which can be paid off with just one shipment of methamphetamine or cocaine

Entrance of the tunnel inside the house where used by Joaquin 'El Chapo' Guzman to escape from the Maximum Security Prison of El Altiplano in 2015

In April 2016, authorities discovered one of the longest narco-tunnels built between California and Mexico. It stretched some 800 meters and was equipped with an elevator.

Typically, depending on the length and complexity, the tunnels can cost anywhere between $1,000,000 and $2,000,000 to construct, which can be paid off with just one shipment of methamphetamine or cocaine.

Guzman, who was once lauded as the ‘master of tunnels’, allegedly sent a number of his cartel engineers to Germany to receive specialized training for underground tunnel construction, which would eventually be put to use to build the escape route used by El Chapo to escape from a maximum security prison for a second time.

‘The Sinaloa Cartel is the principal builder of sophisticated tunnels,’ Mike Vigil, the DEA’s former Chief of International Operations, told InSight Crime last year. ‘The [narco-tunnels] are well worth their weight in gold.’

Last month, Guzman said he wanted his staggering $9.8 billion fortune to go to indigenous Mexican communities rather than be forfeited to the US government, his lawyer said.

The request was made during a series of phone calls between the former kingpin and his mother, sisters and daughter in August.