Kathryn Bolkovac, a Nebraska police officer, takes a lucrative job with a military contractor tasked with helping forge a fragile peace in post-war Bosnia. One night, she oversees a nightclub raid and watches a string of battered girls, some not much older than her own teenage daughter, hobble out-the "whores of war," as one man puts it. But when Kathryn sees chains in a padlocked room and photographs of her co-workers abusing young girls, she begins to trace the evil back to those assigned to keep the peace.

Expect realism and righteous anger from Whistleblower (rated R for intense violence, sexual assault, and language)-based on the true story of a UN peacekeeper who uncovered sex trafficking in Bosnia and discovered that the people supposed to protect the Bosnians were exploiting them.

Rachel Weisz brings a tight-lipped intensity-and at moments, an inspired fury-to the role of Bolkovac, but her character remains opaque. She tells one young girl that she is helping her to atone for the fact that a judge took her own children away, but her reasoning strikes a discordant note. Whistleblower evinces a grim ambition to grind its viewers' faces in the muck of human corruption, but the camera lingers on horrific violence in a way that eventually seems plain sick. The bomb-pocked setting lacks any touch of warmth, even in the safe house where the girls take refuge.

Kathryn can trust no one, and the film plays this masterfully to a suspenseful end. But after Bolkovac's story ends, the real story continues. The contractor, DynCorp in real life, retained its government contracts. In Afghanistan, DynCorp employees hired a child prostitute as entertainment, and in Iraq, badly mismanaged a $1.3 billion contract. Bolkovac blew the whistle but corruption went on, which makes Whistleblower's ending feel a little hollow.