THEY GOT'EM! MEXICO ARRESTS DON PEPE! THE KING OF DOPE!

MEXICO CITY - Federal police have arrested Mexico's "King of Heroin," a powerful drug trafficker allegedly responsible for running thousands of pounds of heroin into Southern California each year, authorities said Thursday.

Jose Antonio Medina, nicknamed "Don Pepe," was arrested in the western state of Michoacan on Wednesday and is being held for prosecution, said Ramon Pequeno, head of the anti-narcotics division of Mexico's federal police.

Medina, 36, ran a complex smuggling operation that hauled 440 pounds (200 kilograms) of heroin each month across the Mexican border in Tijuana for La Familia drug cartel, Pequeno said.

The White House National Drug Threat Assessment says that while heroin use is stable or decreasing in the U.S., the source of the drug has shifted in recent years from Colombia - where production and purity are declining - to Mexico, where powerful drug cartels are gaining a foothold in the lucrative market.

Heroin production in Mexico rose from 17 pure metric tons in 2007 to 38 tons in 2008, with the increase translating to lower heroin prices and more heroin-related overdoses and more overdose deaths, according to U.S. government estimates in a report by the National Drug Intelligence Center.

Border Patrol agents seized 4.8 million pounds of narcotics at border crossings last year, and heroin seizures saw the most significant increase during that time, with a 316 percent jump over 2008.

Mexico and the U.S. are working together to counter a handful of increasingly violent drug cartels that supply most of the illicit drugs sold in the U.S. The arrest came the day after top U.S. Cabinet officials, led by Secretary of State Hillary Rodham Clinton, visited Mexico to underscore their shared responsibility for the country's drug-related violence.

Nearly 17,900 people have died in drug-related violence since President Felipe Calderon launched an assault on cartels after taking office in December 2006.

The bloodshed continued Thursday, when Mexican marines on patrol in the small town of Cerralvo, north of the city of Monterrey, came under fire after ordering a convoy of gunmen traveling in 6 vehicles to stop.

Six of the assailants were killed in the ensuing battle, the navy said. The marine patrol, which was supported by two navy helicopters during the firefight, seized 15 rifles, 10 pistols, 2 grenades and ammunition from the vehicles.

A secretary at the Cerralvo town hall said the shootout took place on the outskirts of town on the highway toward the border with Texas. The shooting was heard throughout the town.

In Ciudad Juarez, a border city of 1.3 million people just south of El Paso, Texas, police found a decapitated man lying in a shopping center parking lot, his head inside a black plastic bag nearby.

Police in Ciudad Juarez also evacuated a grade school after two explosive charges were found on the sidewalk in front of the building. The explosives, apparently of the type used in rock blasting, were removed by soldiers.

In the southern state of Guerrero, the body of a 16-year-old boy was found at a trash dump in the township of Tecpan de Galeana. State police said the body bore multiple gunshot wounds.

Such killings are believed to be the result of drug cartels fighting among themselves for control of the drug trade, a lucrative business estimated to bring $25 billion in cash into Mexico each year.

Federal police in Mexico City said Thursday they had seized $1.7 million in small bills and arrested two Colombians and two Mexicans for allegedly running financial operations for cartels.

Federal prosecutors announced Thursday they were taking over the investigation into the March 19 deaths of two university students who were killed when they were apparently caught in crossfire between soldiers and gunmen in Monterrey.

The deaths of the two students caused outrage in the northern city. Mexican law allows cases involving civilians and soldiers to be tried in either the civilian or military justice system. Thursday's move suggests the case would proceed through the civilian legal system.

Also in Monterrey, a human rights group said a suspected drug trafficker wanted for questioning about a shootout - and the death of a fellow suspect - was in hiding. So was the police chief, who state investigators want to question about the case.

The two trafficking suspects were detained Sunday in the Monterrey suburb of Santa Catarina. They were last seen being put aboard a navy helicopter. On Monday, one of the suspects turned up tortured, killed and wrapped in a blanket.

It was unclear how one suspect died and the other wound up on the run, but the navy has said it simply transported the men to a hospital at the request of local police.

Nuevo Leon state police were sent to question the surviving suspect Wednesday night, but he had disappeared by the time investigators arrived, the state human rights commission said.

Nuevo Leon Gov. Rodrigo Medina said Santa Catarina police chief Eduardo Murrieta should testify before authorities to clear up the mystery. Murrieta had custody of the two suspects after they were detained.

But Santa Catarina Mayor Gabriel Navarro said Murrieta was in hiding because he feared for his life. Murrieta was wounded in a clash that followed the two men's detention Sunday.