TIJUANA, Mexico (Reuters) - Mexican drug gangs near the U.S. border are breaking into police radio frequencies to issue chilling death threats to cops which they then carry out, demoralizing security forces in a worsening drug war.

A state policeman at a crime scene where two police agents were gunned down inside their truck in the border city of Ciudad Juarez, January 20, 2009. REUTERS/Alejandro Bringas

“You’re next, bastard ... We’re going to get you,” an unidentified drug gang member said over the police radio in the city of Tijuana after naming a policeman.

The man also threatened a second cop by name and played foot-stomping “narcocorrido” music, popular with drug cartels, over the airwaves.

“No one can help them,” an officer named Jorge said of his threatened colleagues as he heard the threats in his patrol car.

Sure enough, two hours later the dead bodies of the two named policemen were found dumped on the edge of the city, their hands tied and bullet wounds in their heads.

Cartels killed some 530 police in Mexico last year, some of them corrupt officers who were working for rival gangs. Others were killed in shoot-outs or murdered for working against the gangs or refusing to turn a blind eye to drug shipments.

Violence has hit shocking levels in Tijuana, over the border from San Diego, since President Felipe Calderon launched an army crackdown on traffickers in late 2006, stirring up new wars between rival cartels over smuggling routes.

The drug war is scaring tourists and investors away from northern Mexico, forcing some businesses to shutter just as the country heads into recession this year.

Badly-paid Tijuana municipal police, often accused of collaborating with rival wings of the local Arellano Felix cartel, are badly demoralized, senior officers say.

“These death threats are part of the psychological warfare that organized crime is using against officers,” said Tijuana police chief Gustavo Huerta.

“Before, the gangs began infiltrating the radio after a police execution, which was bad enough, but now they are doing it beforehand and the force feels terrorized,” he said.

WORN-OUT BODY ARMOR

Officers in threadbare uniforms and worn-out body armor say they are no match for drug gangs with powerful weapons and state-of-the art technology. Some police cling to religious trinkets and pray for protection, but many others have taken early retirement.

“I and many of my colleagues are thinking our time in the force is over,” said Olivia Vidal, a Tijuana policewoman with 15 years in the force. “I have three kids. Two are at university. I would never let them follow in my footsteps.”

Drug hitmen are brazenly using pirate radio decoders to flag police murders in advance on the airwave, often playing the brassy accordion-led “narcocorrido” ballads that lionize the escapades of heavily armed, womanizing traffickers.

The gangsters use the decoder to access the radio frequency and then use a transmitter linked to a CD player and a microphone to transmit the narcocorrido music and the threats.

In one recent attack, hitmen killed two officers in their vehicle in Tijuana and then blasted drug ballads over police radio while naming their next targets, just as officers were reaching the first crime scene.

Some gangs sarcastically offer their “condolences” over the air after an execution, broadcasting messages like: “We are so sorry.”