Zetas cartel leader Omar Trevino Morales captured in Mexico

Mexican police and soldiers on Wednesday captured Omar Trevino Morales, widely considered to be the most important leader of the Zetas drug cartel that once carved a path of brutal bloodshed along the country's northern border with the U.S.

National Security Commissioner Monte Alejandro Rubido said at a news conference in Mexico City that the man known as "Z-42" was arrested in a pre-dawn raid in San Pedro Garza Garcia, a wealthy suburb of the northern city of Monterrey.

A simultaneous raid on another street in the same suburb reaped Carlos Arturo Encinas Jimenez, allegedly Trevino's finance chief, Rubido said.

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Tomas Zeron, the attorney general's criminal investigations chief, called Trevino "one of the most dangerous and bloodthirsty criminals in Mexico" and said he faced at least 11 criminal counts including drug trafficking, organized crime, kidnapping and oil theft.

The Mexican government had offered a 30 million peso ($2 million US) reward for his capture on weapons and organized crime charges.

The U.S. Drug Enforcement Administration offered a $5 million reward for his capture, saying he was wanted for drug trafficking. DEA Administrator Michele Leonhart said in a statement, "The Zetas represent the worst in global organized crime: violence, intimidation, corruption, and brutal killings. Today's arrest strikes at the heart of the leadership structure of the Zetas and should serve as yet another warning that no criminal is immune from arrest and prosecution."

The suspect is the brother of Miguel Angel Trevino Morales, described as the most bloodthirsty leader of Mexico's most violent cartel. Miguel Angel was arrested in July 2013, almost a year after Mexican marines killed the Zetas' other biggest leader, Heriberto Lazcano "El Lazca."

Rubido said Omar, 38, took over leadership of the Zetas after his brother's arrest and immediately became a target of their investigation.

The hunt for him caught a break in February when authorities observed someone matching Trevino's description at one of the houses around Monterrey where Encinas, the alleged finance chief, was known to hold meetings, Rubido said. Surveillance was increased until Trevino's identity was confirmed. Authorities discovered he was moving with a smaller than usual security detail to draw less attention.

Just after 3 a.m. Wednesday, federal police and soldiers moved on both locations, Rubido said. Four additional men were also arrested. All six were walked across the tarmac from a military plane at Mexico City's airport and loaded into armoured personnel carriers.

Zetas originally formed by army deserters

The Zetas was originally a gang formed by deserters from an elite army unit and left a trail of brutality, bloodshed and mutilated bodies across northern Mexico during turf battles with the rival Gulf cartel. But much of the violence along Mexico's northeast border now is due to internal battles among Gulf cartel factions.

"The truth is that this is a group that has been fragmented," Javier Oliva, an expert on the drug war at Mexico's National Autonomous University, said of the Zetas. "Their influence is now more on a local level, in townships" rather than the broad, multi-state trafficking corridor they once controlled.

But Oliva said that doesn't mean the Zetas and their internal fight to determine a replacement for Trevino Morales won't turn bloody. He said gunmen or second-tier operators who were active under Trevino Morales may now seek to replace him.

"One would hope that the federal and state governments have taken precautions to avoid this arrest from causing more violence," Oliva said.

The capture of Omar Trevino Morales follows Friday's arrest of another big cartel leader, Servando Gomez, known as "La Tuta." Gomez allegedly led the Knights Templar, a pseudo-religious drug gang that built up control of many sectors of the economy in the western state of Michoacan before it was weakened by an uprising of citizen vigilante groups and a stepped-up federal security campaign.

The two arrests provided much-needed good news for the administration of President Enrique Pena Nieto, who has been battered by a series of scandals in recent months.

"The government needed to show that some of its policies were successful," said Raul Benitez, a security expert at the National Autonomous University. "And in this case, without doubt the strategy against the drug cartels is going well."

Like Servando Gomez, Omar Trevino Morales was captured without any shots being fired.

The Trevino Morales brothers took proceeds from their U.S. drug sales and laundered them by purchasing American quarter horses. That scheme was led by Jose Trevino Morales, a third brother. A jury in Texas found Morales guilty in May of investing $16 million of drug money in the buying, training and racing of horses across the Southwest United States.