On 6 April 2015, a convoy of the Jalisco State Police was ambushed by suspected members of the Jalisco New Generation Cartel (CJNG), a criminal group based in Jalisco. The attack occurred in a mountain road in San Sebastián del Oeste, Jalisco. Fifteen policemen were killed and five were wounded; no CJNG casualties were confirmed. According to police reports, as the police convoy reached a part of the road surrounded by mountains, the CJNG opened fire at the police units from the sides using high-caliber rifles, grenade launchers, and explosives with gasoline. The element of surprise prevented the police from repelling the aggression. The CJNG members burned several vehicles along the highway to halt reinforcements. The attack lasted roughly 30 minutes. When government reinforcements reached the scene, the CJNG gunmen had left.

The ambush was one of the deadliest single-attack incidents against Mexico's security forces in the ongoing Mexican drug war. It was also a rare display of bold attacks against law enforcement. In the past, criminal groups in Mexico tended to avoid direct confrontation with security forces. The attack also showcased the manpower and sophistication of the CJNG. The complexity of the attack showed that the CJNG had expertise in military tactics, guerrilla warfare, ambush and counter-ambush training, and in the use of explosives. According to investigators, the CJNG carried out the ambush to avenge the arrests and deaths of their fallen comrades from government crackdowns.

Ambush and reactions

At around 2:50 p.m. on 6 April 2015, policemen from the Fuerza Única Jalisco, an elite unit of the Jalisco State Police, drove through a mountain road in Soyatán, a rural community in San Sebastián del Oeste, Jalisco. They were driving from Puerto Vallarta to Guadalajara, the state's capital. As they were crossing through the Mascota–Las Palmas highway, a road that was covered by mountains on both sides, they were ambushed by suspected members of the Jalisco New Generation Cartel (CJNG), a criminal group based in the Jalisco. The CJNG gunmen burned several vehicles along the highway to block the road and delay the arrival of potential government reinforcements. As the police units got to a curve, the CJNG gunmen opened fire at them with machine guns and grenade launchers from the side of the mountains. The attack worsened when the CJNG gunmen threw explosives along with jugs of gasoline from strategic locations.

Given the element of surprise, the policemen did not have the chance to defend themselves from the aggression. The policemen that got out of the vehicles were shot by the CJNG. Those who stayed inside them died of calcination. In total, 15 police officers were killed in the ambush. Five more were wounded and transported by helicopter to a wounded-care zone in Puerto Vallarta before being transferred to several hospitals across the Guadalajara Metropolitan Area. Authorities reported them as being in stable condition. No casualties on the CJNG's side were confirmed because the gunmen were able to escape. The police called for reinforcements in Guadalajara. Several police units drove to the area, and a helicopter made it to the scene to provide air support. The Mexican Navy and the Mexican Federal Police (PF) then carried out a search of the surrounding areas to locate the CJNG gunmen. Investigators discovered that the assailants built an encampment in the mountains and waited for the police for as long as 48 hours.

Some of the police units were completely burnt and totaled. Firefighters from Puerto Vallarta were called to the scene put down the flames in the burning vehicles. At the scene, investigators found hundreds of high-caliber bullet casings and detonated grenade fragmentation. At least two vehicles from the CJNG were purposely burnt to block the roads, but investigators were not able to determine if the vehicles were owned by uninvolved civilians whose cars were hijacked by the CJNG to block the road. There were no reported injuries during the road blockades carried out by the CJNG. After the shootout took place, the area was cordoned by law enforcement; the road where the attack occurred was closed for security measures. Several drivers complained because they were trying to leave or go to Puerto Vallarta but were unable to do so. That same evening, Jalisco authorities issued a communiqué confirming that the attack had taken place, but did not specify the casualties until the following morning. The report stated that the attack against the police was a retaliation for the 23 March death of Heriberto Acevedo Cárdenas (alias "El Gringo"), a suspected regional leader of the CJNG. In addition, the report stated that the attack was provoked by the arrest of 15 suspected CJNG members following an assassination attempt against Francisco Alejandro Solorio Aréchiga, Jalisco's security commissioner, on 30 March.

A day after the attack, Jorge Aristóteles Sandoval Díaz, the Governor of Jalisco, called for a meeting with several high-ranking government officials at the Municipal Palace of Guadalajara (es). In the meeting, authorities confirmed the involvement of the CJNG in the attacks. Among the groups present were local security groups in Jalisco, the Mexican Army, the Attorney General of Mexico (PGR), the PF, the Center for Research and National Security, and the Attorney General of Jalisco. Solorio Aréchiga confirmed that the Government of Jalisco did not activate the "Red Code" alert, which is the highest level in the alert system and is used when the state is considered to be under the highest level of danger, despite rumors that it was activated. He went into detail about the ambush, and gave the press more background on the possible motives behind the attack, including the death of El Gringo and previous arrests of suspected CJNG members as part of the murder attempt against him. He also stated that Sandoval ordered the government to increase security measures and operatives across Jalisco, and that they were receiving support from institutions within the Secretariat of Public Security, a branch of the federal government. The government confirmed that the families of the deceased would receive help with funeral costs and with the policemen's life insurance benefits.

Background and possible motives This attack was unusual in the ongoing Mexican drug war (2006–present) because large scale single-attacks against Mexico's security forces were uncommon. Attacks against security forces usually took place because organized crime members were being pursued and wanted to escape. The planned nature of this attack highlighted that organized crime military tactics were advanced and reaching new levels. In addition, though shootings between criminal groups and law enforcement were common, it was rare for criminal groups to come off victorious in gunfights. This attack was the largest death toll on law enforcement's side since 2009. Because of the one-sided death toll on the police's side, the ambush garnered international attention. Jalisco was one of the four states in Mexico that President Enrique Peña Nieto (2012–2018) considered a priority for his national security initiative. Between March 2013 and April 2015, at least 70 government officials were killed in Jalisco. According to official reports from the Mexican government, there were 1,025 homicides linked to organized crime in Jalisco in 2014. This was lower than the year before, which totaled 1,485. These numbers are considerably higher than 2009, when Jalisco reported 679 homicides.

The month before the ambush, on 19 March 2015, the CJNG attacked a convoy of the National Gendarmerie (es), a branch of the PF, in Ocotlán, Jalisco. Eleven people were killed; five of them were police officers. The attacks were part of a larger campaign by the CJNG to avenge the capture or deaths of its leaders. Investigators believe that the attacks were masterminded by Nemesio Oseguera Cervantes (alias "El Mencho"), the top leader of the CJNG and one of Mexico's most-wanted drug lords. The intention of the attacks was to avenge their fallen comrades and show the government their manpower to strike back. On 23 March 2015, El Gringo and his suspected henchmen were driving through Zacoalco de Torres, Jalisco, when they encountered the Jalisco State Police. The CJNG members tried to escape, but their vehicle turned over as they sped away from the police units. Two gunmen opened fire at the police officers and threw a grenade at them.

However, the police was able to neutralize the aggression and kill four of them, including El Gringo. One policeman was wounded in the attack; he was shot in the leg and calf, but was reported in stable condition. At the time of his death, El Gringo was suspected by law enforcement to be the regional leader of the CJNG in Zocalco de Torres and other municipalities of the region. There were 10 pending investigations against him, and he was suspected to be involved in gas theft, kidnappings, and in at least nine homicides. They also believed that he was responsible for a number of attacks against law enforcement, including the gunfight that left four Mexican Army soldiers dead on 12 May 2014 in Guachinango, Jalisco, and the murder of two police investigators in Tlajomulco de Zúñiga, Jalisco on 29 July 2014. According to investigators, El Mencho reportedly ordered the CJNG to carry out attacks against the government security forces in Jalisco as retaliation for El Gringo's death.

On 30 March, suspected CJNG members carried out an attack against Jalisco's security commissioner Solorio Aréchiga while he was driving in Zapopan, Jalisco. Over 100 shots were fired from both sides, but Solorio Aréchiga's bodyguards were able to repel the CJNG's armed aggression and help him come out of the shooting unharmed. Investigators confirmed that this was a direct assassination attempt against Solorio Aréchiga, and that it stemmed from the government crackdowns on the CJNG's leadership structure. A few days after this incident, the CJNG carried out the ambush in San Sebastián del Oeste. Solorio Aréchiga insisted that the ambush was also a result of the extensive investigation and arrests carried out by the government after the assassination attempt. State officials stated that it was likely that the CJNG would carry out more attacks after the ambush against Mexican security forces based in Jalisco. In a year, dating from the day of the ambush and back, 24 law enforcement agents in Jalisco were killed in ambush attacks with similar military tactics as ones used in San Sebastián del Oeste.

Analysis of attack and formations