JEFFREY BROWN: Finally tonight, another front on the Mexican drug war, the deadly struggle that has taken more than 30,000 lives in the past four years.
From a town in northern Mexico, Bill Neely of Independent Television News has our report.
BILL NEELY: She's 21. This is her first job, one of the most dangerous in Mexico. Marisol Valles is the new police chief of one of her country's deadliest areas.
She got the call because policemen in her town were being murdered by drug gangs. Most quit. She was a criminology student, so she took the job.
"I'm doing it," she says, "in the hope of a better, more peaceful life for my town, for my son."
Are you scared for your own life?
"I am afraid," she says, "like everyone here. And I take precautions, but hope is stronger than fear."
She has good reason to be afraid. Rival drug cartels kill each other and anyone who gets in their way. If they can't control a street, they burn it. Whole neighborhoods of Marisol's town are deserted. She commands a force of 10 officers. They have two police cars.
Bullet holes pockmark her office -- on the door, pictures of missing men presumed murdered.
Many people in Mexico say you're crazy to take this job.
"I don't think of myself as crazy," she says. "My plan is not to confront the cartels. I'm not even armed. We're trying a gentler approach."
Keeping an eye on her, Mexican troops. They fight the drug cartels who kill for control of the roads to Texas and the lucrative U.S. market, cartels who have killed many women nearby.
In this town, too, there is a woman police chief in her 20s, or at least there was, until she was kidnapped by armed men just before Christmas. She hasn't been seen since.
The men who appointed Marisol Valles believe she will be safe.
Isn't it irresponsible to put her in this job?
ANDRES MORALES, town clerk, Praxedis, Mexico: I don't think so, because...
BILL NEELY: This is a dangerous job.
ANDRES MORALES: Yes, but it's a dangerous job for all of people who works at public administrations.
BILL NEELY: If the drug cartels want to send a message, they will try to kill her, won't they?
ANDRES MORALES: It's a risk. But someone has to do this job.
BILL NEELY: Behind her, the gun cabinet she keeps empty and the bulletproof jacket she won't wear.
"It's too big for me, anyway," she jokes.
Some call her the bravest woman in Mexico. She says she's just lucky to have a great job. She may need all that luck in her three years as chief of police.
JEFFREY BROWN: We'll have more of Bill Neely's reports about Mexico's drug wars in the coming days.