BUS 174 — ** 1/2 — Documentary; in Portuguese, with English subtitles; not rated, probable R (profanity, violence, drugs, vulgarity, brief nudity).

"Bus 174" unfolds almost like a suspense-thriller, as it tries to keep the audience on the edge of their seats about what will happen next. What's unusual is that this particular film is a documentary.

That — and the film's extensive use of actual newsreel footage of a crime in progress — give it a sort of "COPS" feel. But it's considerably more ambitious than that probably sounds.

Unfortunately, that ambition nearly proves to be the film's undoing, as it is filled with so many digressions and redundant "talking-head"-type interviews that the whole thing starts to get away from the filmmakers. (Also, two hours is much too long for a documentary of this type.)

Still, there's no denying the subject matter is compelling, and the heightened sense of tension goes a long way toward redeeming the film.

The film's title refers to a well-known (at least in its home country) July 12, 2000, hostage incident in Rio de Janeiro. A young would-be robber, Sandro di Nascimento, held up passengers on a bus at gunpoint, only to find himself surrounded by police and the military.

In the hours that followed, the young robber attempted to regain control of the situation by writing a series of cryptic messages on the bus's windows, and, in essence, staging a drama of sorts in front of news crews.

This documentary makes use of that newsreel footage, which makes story all the more vivid. The filmmakers also interview some of the survivors, as well as a police negotiator who tried to defuse the whole situation.

That's plenty of material to work with, but director Jose Padilha also tries to examine what brought di Nascimento to this point, and much of what is shown is not nearly as interesting. The film is also pretty superficial (the poverty-helping-create-criminals thesis was expressed more vividly in last year's "City of God").

"Bus 174" is not rated but would probable receive an R for frequent use of strong sexual profanity and crude sexual slang terms, newsreel footage of violence (shootings and some rioting), drug content (talk about cocaine and inhalant use), and brief, full male nudity. Running time: 118 minutes.

E-mail: jeff@desnews.com