JIM LEHRER: Finally tonight, another of our stories on the Mexican drug war, from the city of Monterrey.
We have a report from Bill Neely of Independent Television News.
BILL NEELY: He doesn't dare show his face. None of them do. Yet they are policemen guarding what was once the safest city in Latin America.
Monterrey is Mexico's richest city, its business capital. But drug cartels want more of the business. Drug money has always been laundered and spent here. These Ferraris are all bought, but no one's picking them up for fear of being targeted. And the fear in Monterrey is growing.
A daylight gun battle in the city center -- it's not unusual. Federal police are struggling to retain control, as cartels mount what's been called an insurgency against the government. They hardly need the cover of darkness, but it's mostly at night that the cartels target the police. And their gunmen are killing them by the carload.
Two policemen have just been shot dead here, ambushed by gunmen who pulled alongside them in two cars. So far today in this city, four police officer have been murdered.
In all, nine people were shot dead that day. More than 20 policemen were killed in Monterrey last month. But that's not the half of it. Monterrey is becoming a city of massacres, half a dozen policemen here, rivals from another cartel there, some beheaded.
The killers leave messages, threats, and the police are resigning in their hundreds.
"We're afraid," he says. "It's getting so much more dangerous." He's seen half his force quit. But the police have a problem. No one trusts them.
MAN: Well, we do trust in the army and in the marines.
BILL NEELY: But not the police?
MAN: Not the police at all.
BILL NEELY: You think they're linked to the drug cartel?
MAN: Yes. Everybody thinks so.
BILL NEELY: Poorly paid officers are bought off by cartels. The corruption runs deep, from officers on the beat to police chiefs, and up further, to mayors, judges, senior politicians.
Mexico is losing faith. Life in its model city is changing. And it's a war the government isn't winning.
MAURICIO FERNANDEZ, mayor of Monterrey, Mexico: Well, there are many reasons that I think we're not winning the war. We have a lot of poor people, that many of them would like to be (SPEAKING SPANISH) or (SPEAKING SPANISH) or any of those...
BILL NEELY: Killers?
MAURICIO FERNANDEZ: Or chief of the mafias.
BILL NEELY: Another day, another atrocity by the mafias, this time a car bomb.
Monterrey is sinking faster than any place in Mexico. The gunmen are pouring in. It's a city under siege. Army, police, government, none of them can control it.
One man told me, if Monterrey is lost, everything is lost in Mexico. The rich, once-safe city is now cowering under the shadow of the gun.
JIM LEHRER: We'll have one more Bill Neely report from Mexico on youth gangs in the drug war shortly.