Close this search box.
Home Argentina Monos


The criminal group known as “Los Monos,” led by members of the Cantero family, has been operating for more than 20 years in the Argentine city of Rosario.

Share Article:


The criminal group known as the Monos, led by members of the Cantero family, has been operating for more than 20 years in the Argentine city of Rosario.

Their sophisticated relationships with members of the security forces, businessmen and other local elites, as well as their use of violence have allowed the Monos to control illicit economies, such as micro-trafficking, throughout the city.

Despite a trial that resulted in many of the group’s leaders and members landing behind bars in 2018, the group continues to operate and contribute to the wave of violence tearing through the city of Rosario.


The criminal history of the Cantero Clan, the family heading up the Monos, began in the late 1990s. At that time, members of the Cantero family, under the patriarchal command of Ariel Cantero, alias “El Viejo,” loaned security services to Rosario’s most marginalized neighborhoods and coordinated marijuana shipments from Paraguay.

Rosario is strategically located as a transit point for drug shipments coming from neighboring Bolivia and Paraguay. The main trafficking route is Route 34 that starts at the border with Bolivia and ends in Rosario.

It was not until the beginning of 2004 that the criminal group set its sights on the lucrative micro-trafficking business in areas they controlled.

As Argentina emerged from one of the severest economic crises in its history, the country was left greatly marginalized and with a high poverty rate. The Monos took advantage of the economic situation to position themselves as the “de facto” authority in large areas to the south of Rosario. They managed this with the help of strong connections with security forces, construction companies that sought land during the post-recession construction boom, car dealerships which the gang used for money laundering, and in politics, which are essential in a country where voting is mandatory.

They started to recruit marginalized youth to work in “bunkers,” small brick structures scattered throughout Rosario’s marginalized neighborhoods, where they would sell drugs in small quantities. Over time, the number of bunkers grew and kids with hands small enough to pass cocaine doses through the bunker windows became known as “soldaditos” (small soldiers.)

Business prospered and the group continued to consolidate, until two high-profile murders led to a wave of violence that put Rosario and the Monos at the center of public attention.

On September 8, 2012, Martín Paz, alias “El Fantasma,” was killed in cold blood in broad daylight in the center of Rosario.

It is believed that El Fantasma had been laundering money for the Cantero family through his car dealership and occasionally transported drugs for them. However, his connection to the Canteros ran deeper. He was married to the sister of Claudio Ariel Cantero, alias “El Pájaro,” the son of Monos leader, El Viejo.

Shortly before being killed, El Fantasma had organized the arrival of a cocaine shipment from Bolivia with Cantero family money. However, the shipment was confiscated by the Argentine police on the Bolivian border. El Fantasma lost the drugs and the money and the Canteros, particularly El Pájaro, saw this as treason.

Eight months after El Fantasma’s murder, in the early hours of May 26, 2013, El Pájaro was shot dead as he left a night club. Following El Pájaro’s death, his brother Ariel Máximo Cantero, alias “Guille,” assumed leadership of the Monos.

El Pájaro’s murder generated a wave of indiscriminate violence. In the week following his death, four people were murdered and the homicide rate in Rosario shot up to fa higher than the national average.

The social pressure generated by the wave of violence forced the government to act. In April 2014, Argentina’s then-security minister, Sergio Berni, led a Hollywood-esque raid by the national police to dismantle Rosario’s bunkers. This militarized strategy has continued under the current administration of President Mauricio Macri.

The crimes also led to one of the most intensive and widely publicized criminal investigations in Argentina’s recent history. The investigation lasted several years and was based primarily on evidence collected through intercepted phone calls. The case shined light on an intricate criminal network that involved criminal groups, the police, and businessmen from Rosario, as well as other Argentine provinces.

On April 9, 2018, in what was widely seen as an historical court decision, the then-leaders of the Monos, Guille and Monchi, were sentenced to 37 and 22 years in jail respectively on charges of illicit association and homicide. El Viejo received a six-year prison sentence for involvement with an illegal organization. Many of the group’s other prominent figures were also sentenced (see below).

Additionally, nine local police agents were found guilty of belonging to the Monos.

The group has managed to keep its drug business alive, however. Despite the group’s leaders being behind bars, violence has continued to be used to intimidate and get revenge on judges, prosecutors and witnesses in Rosario.

In 2018, just days after the group’s current leader, Ariel Máximo Cantero, alias “Guille,” was sentenced to prison, a gunman opened fire on the house of one of the judges. This was just the first of a series of attacks for which Cantero and other members of the Monos, face trial in 2021.

Despite being on trial for ordering attacks on judicial authorities and entities, Cantero directly threatened the judge during a court appearance on August 20. When asked about his profession at the beginning of the court hearing, Cantero responded:  “I contract hitmen to shoot judges.”

Clan members have been transferred to different prisons, with the intention of curbing their communication with the outside world and thereby their ability to influence Rosario’s criminal landscape. Unfortunately, this strategy has had little success.


The Monos operate through family ties, resulting in a unique level of trust.

This was evident when Claudio Cantero was murdered and his younger brother Ariel Máximo Cantero assumed leadership of the criminal organization, along with the family’s foster child, Ramón Manchuca, alias “Monchi,” and Jorge Emanuel Chamorro, alias “Ema,” a family friend and hitman.

A significant part of the criminal group’s leadership is currently behind bars, but this has not stopped the group’s operations.

The group’s leader, Ariel Máximo Cantero, alias “Guille,” is among several members of the Monos currently facing trial for money laundering and ordering attacks on legal authorities and judicial centers during the 2018 trial against 34 of the group’s members.

Cantero is currently completing a 22-year sentence for illicit association and homicide as well a separate 15-year sentence for drug trafficking. In April 2019, Guille was also indicted, along with another member of the Monos, Leandro Vilches, alias “Gordo,” for leading drug trafficking operations from prison between 2015 and 2016.

Ramón Manchuca, alias “Monchi,” the family’s foster child, is serving a 37-year sentence for illicit associations and homicide. Jorge Emanuel Chamorro, alias “Ema,” a family friend and gang hitman, was sentenced to 12 years of prison for illicit associations and being an accomplice to a homicide and 17 years for drug trafficking.

Vanessa Barrios, Guille’s wife, and Jésica Lloan, Ema’s girlfriend, were sentenced to 12 years for coordinating drug production and sales under the orders of their partners while they were held in the Piñero prison, located 20 kilometers from Rosario.

The group’s family patriarch, Ariel Cantero, alias “El Viejo,” who was sentenced to eight years in prison for being a member of an illicit organization, was granted a reduction in his prison sentence during the COVID-19 pandemic for finishing primary school while in prison and was released on parole in 2020 He was, however, re-arrested in April 2022 for allegedly planning a series of attacks on petrol stations and a school in late 2021. The family matriarch, Patricia Celestina Contreras de Cantero, alias “La Cele,” was sentenced to eight years of house arrest on charges of leading a criminal organization.


For the past two decades, the Monos have primarily been focused on the city of Rosario, in Argentina’s Santa Fe province.

The city is a strategically located spot for drug shipments coming from Bolivia and Paraguay. It is also the endpoint for Route 34 that starts on the Bolivian border and ends in Rosario, along which numerous drug shipments are sent.

While the Monos have contacts in other parts of the country, they primarily focus on the Argentina provinces that border Paraguay and Bolivia, from where they receive shipments of marijuana and cocaine.

Allies and Enemies

The Monos’ success was in no small part due to their strong criminal ties to local police, prison staff, businessmen, and even the heads of Rosario’s “barras bravas” or soccer gangs. They also managed to establish links with drug producers and distributors in other provinces in Northern Argentina, as well as in neighboring Paraguay and Bolivia.

These links allowed them to manage their drug retail business almost without interference for years, laundering their illicit profits and managing their business even when while behind bars.

However, two murders in 2012 changed all that. Martín Paz, alias “El Fantasma,” a Monos ally thought to have finally betrayed them and Claudio Ariel Cantero, “El Pájaro,” slain in revenge a few months later in what was seen as a retribution killing, triggered a battle between different factions and criminal groups looking to control the territory.

Members of other familiar clans and smaller criminal organizations, both in size and influence, have tried to challenge the Monos’ hegemony in Rosario. Among the groups challenging the Monos are the Alvarado, Ungaros and the Funes.


Despite being behind bars, the Monos’ leaders have continued to use their connections to keep the group’s criminal activities ticking along.

With a growing drug consumption market in Argentina, Rosario’s criminal groups, including the Monos, continue to have fertile ground on which to maintain operations.

However, the length of prison stays for key members of the Monos suggests that the group’s glory days may be behind them.

0 0 votes
Article Rating
Notify of
Inline Feedbacks
View all comments

Criminal Time is a media organization, we provide regular reports, crime bulletins, crime scene photos, analysis, data, investigations and crime related news.

Our work is costly and high risk. Please support our mission investigating organized crime.

By topic

By country

By person

Criminal Time

© 2024 Criminal Time.

Powered by WordPress VIP