Federal police arrested an alleged leader of a drug cartel that purportedly offered to disband if the Mexican government proves it can protect citizens from other criminals in a western state, authorities said Tuesday.

Jose Alfredo Landa, 37, was in charge of La Familia operations in Morelia, the Michoacan state capital, said Ramon Pequeno, the federal police anti-narcotics chief.

Police surrounded a house outside of Morelia Monday and arrested Landa and three others, seizing an AK-47 and other weapons, Pequeno said at a news conference in which the suspects were paraded before the cameras. Pequeno said that Landa was found with more than two dozen property titles and other documents that he had been using to extort homeowners.

Landa was the second suspected La Familia leader arrested since letters were dropped on streets and e-mailed to journalists last month announcing the offer to disband and negotiate a truce with authorities.

The government of President Felipe Calderon, who chose Michoacan as the first battleground when he deployed tens of thousands of soldiers to fight cartels in 2006, has ignored the letter and refused to comment on its authenticity.

The earlier suspect, Sergio Moreno Godinez, said in a police interrogation video released last month that the gang actually made the offer. Moreno said the cartel is in decline and leader Servando Gomez has suggested they give up.

Pequeno said that Landa, alias "Skinny," told police the offer was intended to improve the image of La Familia.

The federal police often release interrogation videos or details of confessions after major arrests, but defense attorneys often question the reliability of the statements, saying the detainees are frequently pressured into false admissions.

Attorney General Arturo Chavez Chavez acknowledged in September that drug lord Edgar "La Barbie" Valdez Villarreal's account of his drug dealings could not be submitted as evidence because his lawyer was not present. Valdez's attorney said the suspect was handed a script to read out loud.

La Familia, which officials say is Mexico's main trafficker of methamphetamine, captured nationwide attention in 2006 by rolling severed heads into a disco in the city of Uruapan. Shortly afterward Calderon sent thousands of federal troops and police into Michoacan, his home state.

The cartel has fought back with some of the brashest attacks on security forces, including an ambush that killed 12 federal police officers in June.

The gang, however, has sought to convince the public that it is defending Michoacan against other drug gangs. It has distinguished itself by occasionally making public pronouncements and has issued a set of rules for cartel members that proclaim family values and prohibit consuming -- but not trafficking -- hard drugs.

Last week, banners were hung from pedestrian bridges in several Michoacan towns and cities complaining that the federal government has ignored the proposal to disband.