Rating:

A documentary thrill-ride. Blacks and whites marching side by side.

Pimply faced teens throwing up the Nazi salute. Looking at powerful images like these, you might think of distant history: Selma in the '60s, perhaps, or Munich in the '30s. But the terrific new documentary "The Letter" tells a much more recent story — what happened just three years ago in the small city of Lewiston, Maine, when about a thousand Somali refugees moved to town. The new immigrants were sparks for a powder keg, and "The Letter" does an excellent job of capturing Lewiston's explosion.

We meet progressive Lewistonians who invite Somalis for dinner and less-accepting locals who fret that Somalis will take all their welfare money. There's even a white supremacist who babbles on about "Third World people" who "multiply like rats." As it turns out, he's just the tip of the iceberg.

The movie's title comes from a public letter that the mayor of Lewiston published in October 2002, telling the Somalis not to bring their relatives to town. After that, there were white vs. Somali fights at the high school, and even shots fired.

"I called my mother in Somalia," one refugee recalls, "and she said, 'What are you doing in Lewiston? Are you crazy? Come home!' "

Things got worse in January 2003, when several neo-Nazi groups showed up in Lewiston for a protest. The lead-up to the white power rally and the rally itself make up the second half of "The Letter," and that's when the movie really starts to cook.

Tension builds as director Ziad Hamzeh cuts quickly between the supremacists, the counter-marchers and 230 riot police who set themselves in between with nightsticks, tear gas and fire hoses.

In the last 20 minutes, the film moves as breathlessly as a Hollywood thriller — only it's much more frightening, because it's true.