The last several decades of Cambodian politics have been monumentally venal and murderous, and Who Killed Chea Vichea captures its current dysfunctional state in the life and death of one man, the popular and effective labor organizer Chea Vichea.

From the outset of the film, Vichea declares in a posthumous interview that he knows his life in serious danger. That's the price he's willing to pay to relieve Cambodian garment workers of exploitation and unfair treatment. And indeed he does gain many financial and working benefits for his thousands of followers, only to be gunned down in cold blood at a local Phnom Penh market.

What ensues is not criminal justice but a long string of police bungling, political and personal intimidation of witnesses, and the transparent framing of two unfortunate patsies who eventually are sentenced to 20 years in jail. The alibis and testimony of numerous witnesses are ignored and buried. It seems as if everyone knew they were innocent. But the larger message is clear: what happened to Vichea is what might happen to anyone who engages in Cambodian politics or steps on the wrong toes. Everyone apparently knows that, just as Vichea knew it in his opening interview.

This a really outstanding example of investigative journalism, and one must credit the filmmakers for having the courage to follow the story wherever it led. It's a dangerous proposition. I only wish there had been a bit more coverage of the actual life and work of VIchea, and some clearer sense of "Who really did it."

But that's another truth about Cambodia: everyone knows, but saying it too directly will only bring more heartache.

Many people in the US have seen "The Killing Fields," a film about the genocidal brutality of Cambodia's Khmer Rouge and its leader, Pol Pot. Since this regime's overthrow in 1979, and Vietnam's withdrawal from Cambodia in 1989, Cambodia has moved off the international news radar. "Who Killed Chea Vichea?" lets us know that human rights abuses continue in Cambodia, including politically motivated killings of those who oppose the government of Prime Minister Hun Sen.

With eye-dazzling cinematography, excellent editing, and an intriguing narrative, viewers will long remember "Who Killed Chea Vichea?" They will also quickly understand why this documentary has won a half-dozen film festival prizes.

In 55 minutes this documentary explains the last decade in Cambodia through an unsolved murder. Well worth the time.