In nine months of actions against the Beltran Leyva drug cartel, Mexican authorities have taken down three of its four most-wanted suspects.

The latest is Sergio Villarreal Barragan, a scowling figure known as "El Grande," who was captured Sunday along with two other suspects at a luxury home in the central city of Puebla.

Villarreal's capture marks another big blow against the reeling Beltran Leyva organization, which a year ago was considered one of the most formidable drug-trafficking organizations in Mexico.

In early 2009, authorities offered rewards of more than $2 million each for the gang's four suspected leaders, including Villarreal, described as the key operator of the group.

Authorities predicted this week's arrest would prompt more internal shuffling, but said the group is losing strength. "The weakening will be substantial," Rear Adm. Jose Luis Vergara, the navy spokesman, said Monday.

Sergio Villarreal, 40, dressed in jeans and a black San Antonio Spurs T-shirt, glowered Monday as he was paraded before the news media. At 6-foot-6, Villarreal, a former federal police agent, loomed above the other two suspects and the marine guards. They were captured by Mexican marines without a shot being fired.

A military spokesman denied that authorities were led to Villarreal by his rival Valdez, who was arrested Aug. 30 by federal police outside Mexico City. Authorities said Sunday's arrest came after months of investigation.

President Felipe Calderon and aides have sought to depict the rising violence across Mexico as a sign that the cartels are buckling under the pressure of the government crackdown, launched at the end of 2006. Aides say the bloodshed, largely the result of fighting between groups, is part of a process of fragmentation and self-destruction.

The Beltran Leyva group has been mired in conflict for more than two years since splitting from the Sinaloa cartel led by Joaquin Guzman after the arrest of Alfredo Beltran Leyva in early 2008. His brothers and their supporters believe Guzman turned him in.

In addition, the succession battle since the death of Arturo Beltran Leyva in December has been taxing and left the group exposed. Fighting between rival wings has left scores of gang members dead, many beheaded and dumped with goading notes.

Villarreal's arrest was the second bloodless capture of a top drug suspect in recent weeks. Valdez also surrendered peacefully last month. Some have speculated that he turned himself in.

In late July, troops killed Guzman ally Ignacio Coronel after he pointed a pistol at them during an arrest raid. Vergara called the slaying a "watershed" for underworld suspects.

"Criminals know for sure that the federal government has the superior force to capture them," Vergara said. "This is … why they are not showing signs of resistance."