You might expect CNN or PBS' Frontline to do a hard-hitting expose on the Colombian drug cartels, but the National Geographic Channel?

So it is with Critical Situation: The Killing of Pablo, premiering at 8 p.m. today. This compelling documentary looks at the hunt for billionaire drug czar Pablo Escobar in the 1980s and early '90s, during which time he was responsible for the indiscriminate killing of hundreds of people, including 165 policemen.

Escobar rose to prominence as the leader of the Medellin drug cartel thanks to ruthlessness and charm. He built schools and gave generously to the poor, which established him as something of a saint in Medellin. At the same time, he shipped hundreds of tons of cocaine to the U.S., killed rivals, ordered the death of at least one presidential candidate, bribed judges and politicians and swaggered through life as if he was untouchable.

In the early '90s, the new president of Colombia, César Gaviria Trujillo, was determined to change all that. In collaboration with the U.S. Drug Enforcement Agency, he began arresting Escobar's associates and shutting down his drug labs. Escobar responded by putting a bounty on the heads of cops and politicians. Later, as the noose tightened, he began using car bombs to frighten the citizenry and destabilize the government.

This excellent documentary combines news footage with reenactments to show just how powerful Escobar was. In the early '90s he finally surrendered to Colombian authorities under the condition that he not be extradited to the U.S. and that he get to reside in a jail of his own design.

When the government discovered he was running his drug operation from this "prison," it set out to arrest him again. He fled and evaded authorities for more than a year, eventually meeting his Waterloo in 1993 on a rooftop.

This compelling documentary can be violent, and there's a clear dichotomy between Escobar's ruthlessness and his devotion to his family. He had no trouble dispatching his perceived enemies but nearly fell apart when authorities detained his family.

Killing Pablo plays like a real-life thriller: violent, unpredictable and filled with high-tech gadgets. • Ghosts of the Snow is more traditional fare from National Geographic but no less compelling than Killing Pablo.

About 500 rare Siberian tigers roam the border between China and Russia, and when the normally reclusive animals began attacking humans several years ago, authorities in Russia sent researchers to find out why.

The program includes reenactments of the attacks and investigative footage as detectives examine animal carcases and study paw prints in the terrain. Tigers normally attack humans only when they're hungry or feel in danger, but that wasn't true of the cases profiled here. Several sur- vivors recount the attacks and why they still sympathize with the attackers.

Researchers find a number of faults. One tiger was startled during mating season, and one had been shot by a hunter and was bleeding internally. No wonder it was angry.

Siberian tigers generally go for the neck of their prey. So why were some of the humans bitten on the leg?

As researchers try to piece the puzzle together - including forensic evidence - we get incredible footage of the big cats in the wild, although it's never quite clear whether the footage comes from China or from a nature preserve elsewhere in the first world.

In the end, Ghosts of the Snow proves that in the constant battle between nature and man, nature sometimes strikes back.

Critical Situation: Killing Pablo

• When and where: 8 p.m. today, National Geographic Channel

• What: the hunt for Colombian drug lord Pablo Escobar

Hunter and Hunted: Ghosts of the Snow

• When and where: 7 p.m. Saturday, National Geographic Channel

• What: Why have Siberian tigers recently attacked humans in the wild?

pearsonm@RockyMountainNews.com or 303-954-2592