On July 13, Bolivian police arrested Robin Rosales, whom they called a "big fish" in the drug trade. He had a 10-year prison sentence pending, after he was arrested -- alongside two of his brothers -- in May 2000 on cocaine trafficking charges. In 1997 he was arrested and sentenced for the same crime, but was quietly released on a legal technicality.

Five days after Robin's arrest, the family's lawyer, pictured above, was shot at twelve times outside the Ministry of Justice in Santa Cruz, Bolivia's largest city. Understanding why means unraveling the family's long history of associations with the Bolivian drug trade, which, as government officials have repeatedly emphasized, is not so much controlled by local cartels but by an intricate network of local family clans.

The Rosales family is believed to be made up of at least 29 people, many of whom have had repeated brushes with the law since the early 1990s. The family has long been recognized as one of the richest and most powerful in the Santa Cruz province. But their wealth has attracted police attention: in 2008, authorities seized about $7 million of the family's assets: 12 properties, two aircrafts, and an array of luxury vehicles, trucks and satellite equipment. But in one of the typical reverse legal decisions seen in cases concerning the Rosales, a judge in Santa Cruz ordered everything returned. The family is also said to employ a network of informants across Santa Cruz, who keep the Rosales informed via satellite cell phone on the movements of the security forces.

The most renowned member of the family is William Rosales, who was kidnapped in May 2010, during a violent ambush which left six of his bodyguards dead. The case shocked Bolivia, where the type of drug violence seen in Mexico or Colombia is uncommon. Other details of the killings were more worrying: three of the dead bodyguards were Serbian, raising the question of why Rosales had opted to hire Eastern Europeans to protect him. One of the alleged leaders of the ambush, former police officer Orlando Araujo, was arrested soon after the attack, and detailed alleged ties between the Rosales clan and one of the most powerful criminal groups in Brazil: the First Capital Command (Primer Comando Capital - PCC).

According to Araujo, William Rosales -- who has been imprisoned three times -- made contact with the PCC while serving time in a Brazilian jail. Upon completing his sentence, Rosales returned to Santa Cruz and began trafficking cocaine to Brazil on behalf of the PCC, who reportedly paid him in cash or with vehicles. But tensions began to rise after Rosales reportedly decided he did not want to pay the PCC their cuota for every cocaine shipment. His breakaway from the Brazilian group is perhaps one reason why he began recruiting foreigners -- Serbians specifically -- to work as his bodyguards.

As Araujo tells it, Rosales caused more trouble when he kidnapped a car salesman in 2009, who reportedly worked for Paraguayan drug lord Carlos Antonio Caballero, alias "Capilo," another close ally of the PCC. But the last straw apparently came when Rosales reportedly told Bolivian authorities how to find and dismantle a giant cocaine laboratory in northeastern Santa Cruz. At least ten Colombians were arrested at the scene. One day later, Rosales was ambushed. He has been missing ever since, even though the family's lawyer, Denver Pedraza, says that new DNA evidence suggests William is dead.

Pedraza, who is set to defend Robin Rosales in court, received between two to five of the twelve bullets fired at him on July 18. He now blames Araujo and two other former police officers for planning the assasination, all of them linked to the 2010 ambush against William Rosales.

Whoever attempted the hit against Pedraza was willing to take on one of Bolivia's most infamous narco families. But alongside the decision to finally arrest and prosecute Robin Rosales for his crimes, nearly a decade after he was inexplicably released, the assasination attempt against Pedraza is another sign that pressure is rising against the Rosales, who have long operated with impunity in Santa Cruz.

The family's deep hold on certain elements of the judicial and law enforcement authorities in Santa Cruz seems evident. The sheer number of Rosales brothers -- Jesus, Ruan, Johnny, Victor, Wilfredo -- who have been investigated or sentenced for drug trafficking, then allowed to walk free, points to the family's infiltration of local institutions. The ambushing of William Rosales was a sign that the family's position in the criminal underworld is slipping. Meanwhile, the arrest of Robin may be a sign that the family will finally face increased pressure from another direction: the state.