Lawmakers sought Thursday to question an imprisoned gang leader suspected of having ordered the onslaught of violence that killed nearly 200 people in and around Brazil's largest city last month.

Marcos Willians Herbas Camacho, known as Marcola, heads the First Capital Command, one of Brazil's most notorious organized-crime groups, better known by its Portuguese initials PCC.

The PCC on May 12 unleashed a weeklong Sao Paulo killing spree that included uprisings in more than 70 prisons and attacks against police stations with grenades and automatic weapons. The attacks were triggered after authorities sought to transfer PCC leaders to remote lockdowns.

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The lawmakers said they hope to find out if Camacho was tipped off to the planned police crackdown against his group. Maria Cristina Rachado and Sergio Wesley da Cunha, two of the gang's lawyers, allegedly bought a tape of police telling lawmakers of their plans two days before the attacks began.

The two attorneys, who denied any wrongdoing, have been ordered to turn in their passports pending an investigation.

The lawmakers will also ask the PCC leader, currently held in the Presidente Bernardes state penitentiary, 540 kilometers (335 miles) west of Sao Paulo, if he negotiated an end to the violence with Sao Paulo city and state authorities,

Led by congressman Moroni Torgan, the nine-member congressional panel also is investigating PCC's alleged involvement in arms trafficking.

Camacho "is the leader of a gang that has had ample access to contraband weapons," Raul Jungmann, a member of the investigative commission, told the O Estado de Sao Paulo newspaper. "We want to know the route used to traffic these weapons and the PCC's connection to national and international arms trafficking gangs."

The PCC was founded in 1993 by hardened criminals inside Sao Paulo's Taubate Penitentiary but remained a relatively obscure group until February 2001, when uprisings in 29 prisons across the state killed 19 inmates.

At the time, it was the biggest prison rebellion in Brazil's history and took police 27 hours to crush.

The PCC and other gangs were originally formed to pressure authorities to improve prison conditions, but they quickly abandoned that objective and began using their power inside prisons to direct drug-dealing and extortion operations on the outside.

The PCC used violence to rapidly dominate other prison gangs and became the most powerful organized-crime group inside and outside Sao Paulo's prison system.

There are no official numbers on the gang's size, but estimates go from a low of 10,000 to a high of 100,000 in and out of prison. Gang members are believed to be involved in drug and arms trafficking, bank holdups, kidnappings, extortion and killings.