MEXICO CITY, (Reuters) – Four decapitated and  mutilated corpses were strung from a bridge in a popular  getaway outside the Mexican capital yesterday, the latest  atrocity as the country battles an escalating drug war.

The bodies of the four young men were discovered early yesterday, hung upside down by their feet from a bridge near a  wealthy area of Cuernavaca, a leafy city about an hour outside  Mexico City, where many of the nation’s elite own homes.

The victims’ genitals, index fingers and heads had been cut  off, according to a statement from the attorney general’s  office in Morelos state, which includes Cuernavaca.

Their heads and genitals were found nearby, along with a  handmade sign, the statement said.

“This will happen to everyone that helps the traitor Edgar  Valdes,” the placard read, referring to a leading drug capo  whose real name is Edgar Valdez.

It was signed C.P.S., the initials for the South Pacific  Cartel, a relatively new drug gang that has claimed  responsibility for other gruesome killings.

Drug violence has escalated across Mexico as President  Felipe Calderon goes after powerful cartels and as rival gangs  fight over smuggling turf. More than 28,000 people have died in  drug violence since Calderon took office in late 2006.

While much of the bloodshed is centered in northern Mexico,  violence has climbed Cuernavaca, a once-quiet colonial city,  since security forces killed a top drug lord, Arturo Beltran  Leyva, in a shootout there in December.

His death kicked off a power struggle within his cartel,  and rival gangs have been seeking to co-opt his territory.

Valdez, a Mexican-American known as ‘La Barbie’ due to his  blond hair, is a leading contender to head the Beltran Leyva  cartel.