Capote (15) <!-- none onestar twostar threestar fourstar fivestar -->

The title suggests a biopic, but Capote is a far more intelligent, elusive and disturbing creation than anything that genre could offer. Whereas Walk the Line, and others like it, provide a one-thing-after-another chronicle of their subject's ups and downs, this film devotes itself to a particular period that illuminates not just the story of a writer but the writing of a story, and the moral implications that flowed from it. Yes, it has a knockout performance at its core - what biopic now can afford not to? - but it's at the service of larger truths about guilt, trust and personal responsibility.

It begins in November 1959 when Truman Capote, 35 years old, flamboyantly gay and feted as a great Southern writer, notices a small news item in The New York Times. It concerns the murder of a farmer, Herbert Clutter, and his wife and two teenage children, at their home in Holcomb, Kansas. He proposes to go there and investigate this outrage for a series of articles in The New Yorker, not to write a "true crime" thriller - the killers are not yet caught - but to gauge the impact of these murders on a backwater community. Taking their cue from Gerald Clarke's 1988 biography of Capote, the director Bennett Miller and writer Dan Futterman set it up initially as a fish-out-of-water story: how did this effete, fluttery, lisping creature manage to win the trust of the plain-speaking folk of rural Kansas?

The answer seems to reside in the person of Nelle Harper Lee, Capote's childhood friend and soon to be famous herself as the author of To Kill a Mockingbird. Capote took Nelle along as his assistant, and while he flounced around in his ankle-length camel coat, she effected introductions and got the ball rolling: soon the pair were chatting with the locals and having dinner at the house of the police's chief investigator.

Nelle is played by Catherine Keener, the least showy of the film's three major performances; in her quietly sympathetic way she starts out as Capote's companion and ends up as his conscience. Capote himself is played, in a remarkable impersonation, by Philip Seymour Hoffman, his babyishly high voice and soft roly-polyness an innocent counterpoint to the incisive, calculating mind. Without ever taking notes or using a tape-recorder, he could interview people and then write it up almost verbatim afterwards.

Once the two killers, Perry Smith and Dick Hickock, are apprehended and brought back to Kansas, Capote visits them and immediately twigs that he's got more than a magazine article: he's got a whole book, specifically "the non-fiction book of the decade". (The concept of modesty never troubled him.)

There's a chilling moment when he stares at Smith, like a cobra sizing up a mouse, and we sense a hideous Faustian pact about to be struck. Hickock is almost written out of the picture, but Clifton Collins Jr is heartbreaking in the role of Smith, a delinquent since the age of eight and, following the desertion of his father, a wretched punchbag of institutions. His brother and one of his two sisters had committed suicide. He was articulate and sensitive withal, and, as the film recounts it, he sees in his new friend Truman a possible lifeline; as long as he helps to pay their defence costs, the killers may yet escape the hangman's noose. Capote, also from a broken home, finds a kindred spirit in Perry: "It's like we grew up in the same house," he says to Nelle, "but when it was time to leave, I went out the front door and he went out the back."

Over a five-year stretch of appeals and delays the murderers become a cause célèbre, and all the while Capote works away at his book, its title kept secret from Perry: In Cold Blood. As the years drag on, you begin to realise who the film is putting on trial. It's not Smith and Hickock - they confessed to the murders from the off. It's not the police or the judiciary, though plainly the film is appalled by the sentence of the court, a legal strangulation - also in cold blood. What's really in the dock is the ruthlessness of literary creation, personified in Capote. First, he gouges out of Perry what the story requires - an account of the murders - and then frets about not being able to finish the book until the killers are executed. "They're torturing me," he whines, on hearing of another stay of execution.

After In Cold Blood was published in 1965, Kenneth Tynan wrote of it in The Observer: "For the first time, an influential writer of the front rank has been placed in a position of privileged intimacy with criminals about to die, and - in my view - done less than he might have to save them." It provoked a furious response from Capote, who complained of "bullyboy chicanerie", but the film essentially backs Tynan's view. Their Capote is a liar and a coward who abandoned his friends when they needed him. The film-makers append a sharp moral epilogue; after In Cold Blood, they note, Capote never completed another book, implying that he was too guilt-racked. Well, maybe, but alcohol was his more likely nemesis.

Two things are beyond doubt. One, In Cold Blood is the great book Capote intended it to be. And two, its author was a monster of egomania. In a scene at the 1964 premiere of To Kill a Mockingbird, Nelle, happily aglow with her success, sidles up to Capote to ask him how he's enjoying himself. But he's brooding on his stalled book, and nothing can pierce his magisterial self-pity. "I don't know what all the fuss is about," he mutters of the hoopla around his friend. It was Truman's show, or no one's.