Review: Conviction (15)***

She collected her first Oscar in 2000 for her scintillating portrayal of a murdered transgender teenager in Boys Don't Cry. Five years later, Swank was back at the podium for her revelatory performance as a gutsy boxer in Clint Eastwood's tear-jerker, Million Dollar Baby.

Now, the Oscar-winning actress gets beneath the skin of another crusading real-life heroine in Conviction.

Inspired by the story of a sister's unwavering devotion to her jailbird brother, Tony Goldwyn's film condenses an extraordinary 18-year quest for justice into a lean 107-minute courtroom thriller. Betty Anne Waters (Swank) is a wife and mother of two in Massachusetts, who has always defended her troublemaker older brother, Kenny (Sam Rockwell).

In 1980, Kenny is questioned about the murder of diner waitress Katharina Brow but he is released – to the chagrin of local cop Nancy Taylor (Melissa Leo). Two years later, ex-girlfriends Roseanna Perry (Juliette Lewis) and Brenda Marsh (Clea DuVall) testify against Kenny and seal a murder conviction, resulting in a life sentence without parole.

Betty refuses to accept the verdict and puts herself through law school in order to prove her brother's innocence. Conviction is a remarkable true story that provides Swank with a meaty central role that wrings tears and fury in equal measure.

The actress doesn't strike a false emotional note, she gels convincingly with Rockwell as the hot-headed prisoner, who seems worryingly capable of the brutal crime and Mini Driver, as Betty's spunky law school pal, Abra Rice generates some much needed flashes of comic relief amid all of the legal wrangling.

Screenwriter Pamela Gray stacks the odds heavily against Betty and Abra, so when it seems they might have finally discovered a fatal flaw in the prosecution's case it leaves us cheering in the aisles.

The seriousness of Kenny's situation is brought home when one character observes: "If Massachusetts had the death penalty, he'd be dead by now."

On one point at least, the law worked in his favour.