José Manuel Sierra Sabogal, alias “Zarco Aldinever,” second-in-command of the Second Marquetalia (Segunda Marquetalia), was allegedly killed in an August 5 ambush in the southern reaches of the Colombia-Venezuela border, according to a statement from the group. The Second Marquetalia is a dissident group of former fighters from the Revolutionary Armed Forces of Colombia (Fuerzas Armadas Revolucionarias de Colombia — FARC), also known as the ex-FARC Mafia.

The statement accused the National Liberation Army (Ejército de Liberación Nacional — ELN) of carrying out the attack using explosives and said it also claimed the lives of four other fighters. However, Colombian authorities have so far been unable to independently verify the claims.

*Sierra Sabogal’s death, which occurred during an ELN attack near the Colombia-Venezuela border, was confirmed on August 11 by Colombia’s Defense Minister, Pedro Sánchez.

The Second Marquetalia accused “Pedro Pablo” or “Copete,” commander of the José Daniel Pérez Carrero Front of the ELN’s Eastern War Front, of orchestrating the ambush. He allegedly invited high-ranking members of the Second Marquetalia to a meeting to lure them into the ambush.

“The ELN acted with malice and treachery. They carried out premeditated simultaneous attacks on other Second Marquetalia units located in the region,” the group said in the statement.

The killing is linked to a series of recent armed confrontations between the ELN and Second Marquetalia in the municipality of Maroa in Venezuela’s Amazonas state, which local sources began reporting to InSight Crime on August 3. The battles between both groups, according to those reports, took place along the border with the Colombian department of Guainia.

Colombian President Gustavo Petro confirmed the armed confrontation between the guerrilla groups. “The ELN has entered into war with the Second Marquetalia and their conflict extends into Venezuela, where they have already killed people,” the president said in a post on X.

SEE ALSO: Major Criminal Powers Dispute Key Corridors in Colombia

Before this fighting, both the ELN’s Eastern War Front and the dissident Acacio Medina Front, an ally of the Second Marquetalia, had maintained certain financial arrangements and territorial divisions along this part of the border. This allowed them each to manage the area and oversee illegal mining in Amazonas, as well as the drug trafficking routes that cut through this area.

Zarco Aldinever had been in the crosshairs of Colombian authorities. They accused him of being one of the main suspects behind the June shooting of Senator and presidential candidate Miguel Uribe Turbay in the capital city of Bogotá.

The breaking down of the guerrilla alliance in this strategic border region may lead to further military advances from the ELN and spark a new conflict with major implications for both Colombia and Venezuela.

After Hugo Chávez became Venezuela’s president in 1999, he welcomed many FARC commanders into the country who went on to establish operations in several border states. However, when President Nicolás Maduro rose to power in 2013, he established more favorable relations with the ELN. With the tacit support of his regime, the ELN began to expand its operations across the border, eventually displacing some of the dissident FARC factions still there.

The latest flare-up between the ELN and ex-FARC Mafia comes about eight months after the start of another conflict between the guerrilla groups. In January 2025, the ELN launched a violent assault on the ex-FARC’s 33rd Front in the contested Catatumbo region, which is one of the world’s top cocaine-producing areas.

SEE ALSO: Colombia’s Peace Efforts Spark Criminal Disputes and Divisions

With the ELN also controlling key territory on the Venezuelan side in the state of Zulia, this cemented the guerrilla group as the top armed actor on the northern part of the border, granting them access to drug trafficking routes leading to dispatch points in Venezuela.

The ELN’s latest confrontation with the Second Marquetalia in the south suggests this may be the next key battleground for control of the border.

Unlike prior fighting, this conflict may develop more on the Venezuelan side. That is largely because the ex-FARC Mafia’s Acacio Medina Front has more military capacity on that side and can rely on more than a decade of experience operating there. Illegal mining in Amazonas and the drug trafficking corridors near Brazil represent hugely important financial resources for both groups, making it unlikely that either will cede control without a fight.

There is also the risk that the confrontation could expand further north into Venezuela’s Apure state, which borders the Colombian departments of Arauca and Vichada. The Second Marquetalia maintains a strong presence there, particularly in the town of Elorza in the municipality of Rómulo Gallegos. This has long been the preferred place for ex-FARC commanders to operate, and they have taken over ranches and set up camps in the region.

The alleged killing of Zarco Aldinever would add him to a growing list of FARC dissidents killed in Venezuela. Other infamous commanders killed there include Miguel Botache Santanilla, alias “Gentil Duarte,” Seuxis Pausías Hernández Solarte, alias “Jesús Santrich,” Hernán Darío Velásquez Saldarriaga, alias “El Paisa,” and Henry Castellanos Garzón, alias “Romaña.” The Second Marquetalia’s top leader, Luciano Marín Arango, alias “Iván Márquez,” was also gravely injured in Venezuela.

This article, written by the Venezuela Investigative Unit, was originally published by InSight Crime, a Medellín-based foundation dedicated to the investigation and analysis of crime and security in Colombia and Latin America. It has been generously shared with Finance Colombia under a Creative Commons license.

This grim reality was made evident in late January when the army seized more than 2,600 improvised explosive devices (IEDs), including landmines belonging to the National Liberation Army (Ejército de Liberación Nacional – ELN) in Tibú, in the Catatumbo region. Just days earlier, authorities had confiscated 300 landmines in the same area from FARC dissidents. Roads, rural paths, and farms in the region have become impassable.

The increase in demining efforts, landmine seizures, and suspected minefields reported by Colombian authorities in 2024 underscores that, despite the historic decline in landmine use since the 2016 Peace Agreement, criminal groups in the country continue to deploy these devices in their territorial disputes.

Throughout 2024, Colombia’s Office of the High Commissioner for Peace reported 998 incidents related to anti-personnel mines (APMs) and unexploded ordnance (UXO), including demining activities, reports of suspected minefields, and the seizure of these devices, most of which were handmade.

These figures represent an over 11% increase compared to the previous year, which saw 896 incidents. The upward trend has continued since 2021, when 316 incidents were recorded, followed by 412 in 2022. Experts consulted by InSight Crime agree that no single factor explains this surge.

A staggering 94% of the reported incidents were related to demining operations. Increased military activity in strategic areas and greater accessibility to former conflict zones—once heavily mined during the war between the Revolutionary Armed Forces of Colombia (Fuerzas Armadas Revolucionarias de Colombia – FARC) and the state before the 2016 Peace Agreement—account for many of these cases. However, other areas remain inaccessible to both military and humanitarian demining operations due to the control exerted by armed groups.

In Cauca and Nariño, the number of incidents surpassed those recorded immediately after the Peace Agreement: 58 and 69 incidents, respectively, that year. A similar trend has been seen in other departments with lower historical mine activity, such as Guaviare, Casanare, Bolívar, and Cesar.

Although Colombia signed the Ottawa Treaty banning the use and destruction of anti-personnel mines in 1997, it wasn’t until 2016 that the country’s largest guerrilla group and primary user of landmines—the FARC—committed to demining efforts as part of their demobilization.

“In the years following the Peace Agreement, the impact of landmines had dropped dramatically. Now, we are seeing figures reminiscent of the early post-agreement period, with the added problem that today, civilians are more affected than military personnel,” said Camilo Serna, director of the Colombian Campaign Against Mines (Campaña Colombiana Contra Minas), in an interview with InSight Crime.

Below are the three main reasons why landmine use has resurged in Colombia.

1. Criminal Disputes

Military pressure and ongoing territorial disputes in an increasingly fragmented criminal landscape have led some armed groups to resume planting landmines.

In Arauca, bordering Venezuela, authorities reported 101 incidents, mostly in the municipalities of Arauquita and Puerto Rondón, where the ELN’s Eastern War Front (Frente de Guerra Oriental) and the FARC dissidents’ 10th and 28th Fronts operate.

In Cauca and Nariño, key departments for coca cultivation, cocaine production, and trafficking corridors to Ecuador, 142 and 318 incidents were recorded, respectively. Most incidents occurred in the municipalities of Argelia and Tumaco, where FARC dissident factions and the ELN are locked in violent battles for control of these illicit economies.

SEE ALSO: BACRIM Turn to Landmines in Colombia

“Today, armed groups are fighting each other and using landmines against one another. It is no longer a tactical tool primarily used against government troops moving through an area,” Serna explained.

In Catatumbo, a strategic border region with Venezuela, the ELN’s Northeastern War Front (Frente de Guerra Nororiental) has been clashing with the FARC dissidents’ 33rd Front since early January. Landmine use in this area has also prevented authorities from conducting demining operations for years.

According to Colombia’s Deputy Inspector General for Peace Agreement Monitoring, Javier Sarmiento, who has been tracking the humanitarian crisis in Catatumbo, the presence of landmines has made it impossible for over 50,000 displaced people to return home safely.

In other strategic regions for organized crime—such as Chocó, Cauca, and Arauca—increased military presence and demining operations have prompted armed groups to use more explosives to defend their territories.

2. The Fragmentation of FARC Dissidents

In 2024, Colombian authorities attributed 618 landmine-related incidents to the various dissident factions of the FARC. These figures, alongside those from 2023 (638 incidents), mark the highest landmine use by these groups since the Peace Agreement. Before then, FARC dissidents had never been linked to more than 222 such incidents in a single year.

The fragmentation of these groups—previously divided between the Estado Mayor Central (EMC) and Segunda Marquetalia but now splintering even further—has fueled clashes where landmines are a key battlefield tactic.

The ELN, a long-time user of landmines, was responsible for 164 of the incidents recorded in 2024.

Beyond the ELN and FARC dissidents, other armed groups were responsible for 47 landmine-related incidents in 2024—the highest number ever recorded for this category.

SEE ALSO: Gaitanistas Landmines are Guerrilla Tactic from Colombia’s Dark Past

Among them, the Gaitanista Self-Defense Forces of Colombia (Autodefensas Gaitanistas de Colombia – AGC) stand out. Though they typically use direct armed force to exert control, their increasing involvement in landmine incidents suggests knowledge transfer. Following the FARC’s demobilization, some former guerrilla fighters were recruited by the AGC, bringing new tactics to the group’s military operations.

Disputed territories—where the ELN, FARC dissidents, and AGC are vying for control—are the main hotspots for landmine replanting in Colombia.

3. The Rise of IEDs

IEDs can be built using easily accessible materials, some of which have become more durable. Technological innovations, such as the use of PVC tubes, have extended the lifespan of these devices by better protecting the internal ignition mechanisms, which may include electronic triggers or more sophisticated pressure-activated systems.

“It is now extremely difficult to control because numerous groups and individuals know how to build both command-detonated improvised explosive devices and victim-activated landmines,” an anti-personnel mine expert told InSight Crime on the condition of anonymity for security reasons.

In the end, the combination of ongoing armed group conflicts, tactical knowledge transfer between the key former FARC factions at the heart of the conflict, and the ease of manufacturing these devices has severely hindered Colombia’s demining efforts.

This article, written by Beatriz Vicent Fernández, was originally published by InSight Crime, a Medellín-based foundation dedicated to the investigation and analysis of crime and security in Colombia and Latin America. It has been generously shared with Finance Colombia under a Creative Commons license.