CBS News correspondent Bill Whitaker reports that 28 officers have been killed so far this year -- double last year's toll -- in an escalating war against rich, ruthless drug cartels.
"When an officer dies, you feel the weight of the death," Leyzaola said. For Leyzaola, there's an extra burden -- cartel killers threaten to murder five officers a week until he leaves office.
"To even consider that would make me an accomplice of the cartels," he said. "I will never resign."
This wasn't what he expected when we met him a year ago. New on the job, the former army Lt. Colonel was gunning for the drug gangsters.
"If the cartels only understand the language of violence, then we are going to have to speak in their language and annihilate them," Leyzaola said last year.
Easier said than done. Leyzaola soon realized he didn't just have to clean up the drug criminals off the streets. He had to clean them out of his own police department. He says he investigated all 2,200 officers; 460 were fired or, like some officers, jailed for having ties to drug cartels.
"We have prosecuted commanders, chiefs, officers, those who served as the eyes and ears of the drug cartels in the department," Leyzaola said. "We have declared war against these criminals. They must understand, to face a cop is to face their enemy."
Flush with drug profits, the cartels have more fire power than ever; an anti-aircraft gun was seized from gangsters near Mexico City. They're more brazen than ever. In central Mexico, cartel thugs dressed as police broke 50 inmates out of a high security prison -- then drove off in police cars. In Michoacan, they tortured and killed 12 federal agents and piled their bodies by the road. This year in Juarez, the world's deadliest city, urban warfare between rival gangs has taken at least 2,469 lives. That's 862 more lives than last year's grisly record of 1,607 drug-related killings.
In Tijuana, while Leyzaola was rebuilding his police department, the cartels were building too -- six drug tunnels discovered under the U.S.-Mexican border in the last year.
CBS News got an exclusive look at one of them. It's about 33 feet deep, and 166 feet long. Authorities caught and stopped the cartels just 50 feet short of the U.S. border.
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As for Leyzaola, he always travels with 15 body guards, all the time.
After a cartel tried and failed to bribe him, it tried to kill him. Using military uniforms and camouflaged vehicles, they'd planned to blow up police headquarters. The foiled plot was the fourth attempt to assassinate him.
"I'm fighting for Mexico. I will continue fighting until my last days," he said.
Fighting a war that seems to have no end.