Oct. 10, 2012 -- Heriberto Lazcano, aka "Lazca" the leader of the feared Zetas Cartel, was killed by Mexican marines this weekend, in a remote area of northern Mexico.
Lazcano was accused of ordering the killings of hundreds of people, including investigative journalist Francisco Ortiz Franco.
But just how scary is his organization? And what explains its violent acts?
We have compiled a list of the Zetas most outrageous acts of violence. Look at this list, and you will realize there is an eerie logic to the drug gang's actions: winning the war against other cartels.
1. The San Fernando Massacre, April 2011
In April 2011 the Zetas intercepted several buses that were headed towards the border towns of Reynosa and Matamorros, kidnapped people riding in those vehicles and then executed them en masse in a ranch near the town of San Fernando.
It is believed that 193 people died in the 2011 San Fernando Massacre.
Edgar Huerta, a Zetas member who was involved in the incident and was captured by Mexican police, told officials that the Zetas had carried out these executions because they feared that the rival Gulf Cartel was sending reinforcements to Reynosa and Matamorros from other areas of Mexico.
According to Huerta, people who were thought to have links with the Gulf Cartel were pulled off buses, tortured and executed.
2. The Apodaca Prison Riot, February 2012
On February 19, 2012, Zetas members initiated a prison riot, which led to the death of 44 inmates at the Apodaca penitentiary in Nuevo León State. During the confusion that was generated by the riot, 30 members of this gang also escaped from the prison.
In the days following this incident, a spokesman from the Nuevo León state government told journalist Salvador Camarena, that a group of prison wardens had allowed members of the Zetas to cross into a building where members of the Gulf Cartel where being held. Armed with knives and other weapons made in prison, the Zetas massacred their enemies.
The riot was believed to be part of a plan to help important members of the group escape from jail.
3. The San Fernando Immigrant Massacre, August 2010
On the 24th of August 2010, the Mexican military found a mass grave with the bodies of 72 undocumented immigrants, in a ranch near San Fernando, Tamaulipas State.
The immigrants came from Honduras, El Salvador, Ecuador and Brazil. They were trying to make their way to the U.S. border.
Zetas member Edgar Huerta, who was captured in 2011, told investigators that the migrants were intercepted and then killed because the gang feared that they were going to be recruited by their rivals, the Gulf Cartel.
The Mexican government first got news of the incident from an Ecuadorean migrant who was in the group. He survived a shot to the neck, played dead, and then walked more than 10 miles through the arid countryside around San Fernando, until a local person he ran into, directed him to a Mexican military garrison.
4. The Monterrey Casino attack, August 2011
On August 25, 2011 a group of armed gunmen working for the Zetas, entered the Casino Royale in Monterrey. They shot some clients, doused the entrance to the building with gasoline and set it on fire, killing at least 52 people who remained trapped inside the building.
Steve Dudley, director of Insight Crime, wrote that the attack on this casino could be part of a war that Mexican cartels are waging for control of gambling houses, which enable cartels to launder their drug money.
According to Dudley's hypothesis, the Zetas attacked the Casino Royale and other gambling centers in Monterrey, because these places were connected to the Gulf Cartel.
5. 49 Mutilated Bodies in Cadeyreta, Nuevo Leon, May 2012
On the 13th of May, 2012, Mexican police found 49 mutilated bodies on a road that leads from Monterrey to the U.S. border, in the municipality of Cadereyta. A letter "Z" was spray-painted on a wall near the site where the bodies where found, but the Zetas denied they had committed this atrocity.
A week later however, Mexican officials arrested a Zetas member that was allegedly linked to this incident. His name is Daniel de Jesus Helizondo Ramirez, but he is more widely known as "El Loco." El Loco told Mexican officials that he had been told to dump the bodies in Cadereyta by the Zeta's second most important commander Miguel Angel Treviño.
Insight Crime notes that it is strange for the Zetas to deny a crime, and then confess to it. The website believes that the massacre could have been committeed by a local cell of the Zetas that acted without the blessing of top officials from the gang. Another possibility, according to Insight Crime is that top leaders of the gang did authorize the killings, but then wanted to disassociate themselves from the incident, due to the government's strong response.