“What you’re fixin’ to see is a true story.” So says the title card at the very start of Richard Linklater’s Bernie, and it tells you everything you need to know about the movie. A lot of unbelievable things happen, but they closely follow events that actually took place in Carthage, Texas, in 1996, and Linklater tells the tale with genial down-home charm. Making a black comedy out of a real-life murder is tricky business, but Linklater pulls it off.

16 years ago, Bernie Tiede (Jack Black) shot Marjorie Nugent (Shirley MacLaine) in the back four times, killing her. Bernie was known around town as an eccentric but lovable guy; a funeral director who also directed and starred in musicals at the local theater, who wore Hawaiian shirts on his days off and gave generously to various charities. Marjorie, on the other hand, was regarded as the meanest, nastiest, and wealthiest piece of work in all Carthage. We see her whack a gardener with a broom and fire a black employee for stealing her car because he took it in for repairs. Nobody in town wanted to be in the same room with Marjorie, which is why it’s so interesting that Bernie essentially became her live-in servant.

Bernie was known to check up on all the widows whose husband’s funerals he presided over. It’s also known that more than a few developed crushes on him. At first, Bernie’s actions seem cold and manipulative, like he’s getting in Marjorie’s good graces so that he can steal her fortune. But the film throws a few curveballs our way. After Linklater shows us a Bernie who might be a devious conniver, he shows us a Bernie with genuine affection for Marjorie. We see Bernie use Marjorie’s money for his own extravagant purposes, then we see the depths to which he degraded himself by remaining in such close proximity to her. By the time he snaps and kills her, we have no idea if he did it on purpose or if he just couldn’t take it anymore and acted on impulse.

The film’s ingenuity lies in its structure. Questions will appear on the screen (“Was Bernie gay?”), and then all manner of Carthage townsfolk drop in to give their opinions, Black and MacLaine’s scenes playing like the best dramatic re-enactments ever. Some of these folk are actors, and some of them are real; it’s impressive how hard it can be to tell which is which. When Bernie winds up in court near the end, we see very little of the trial besides both sides’ closing arguments. I was a little taken aback at first, but then I realized it made perfect sense: we the audience have been treated as the jury, with the various Carthaginians as first-hand witnesses to the bizarre happenings. Linklater lets you draw your own conclusions, a surprisingly difficult thing to do.

Well, okay, he’s also pretty sympathetic to Bernie, but that’s the whole point of the movie. How couldn’t you be? The trial had to be moved 50 miles away from Carthage for fear that the jury would be so biased in his favor that they wouldn’t possibly hand down a conviction. I don’t think I’ve ever heard of something like that before, but that’s just how gosh darn sweet and nice Bernie is. Jack Black is mighty good as Bernie, with a light twang in his voice and a skip in his step. There are extended takes of Black doing odd or macabre things, such as performing in a big musical number or giving an ill-timed pep talk to a Little League team, that feel like they go on forever and are excruciatingly funny as a result. You just want to give the guy a hug even if he did shoot the old lady.

Shirley MacLaine gives good glower as Miss Nugent, occasionally showing a crack in her ice queen facade before steeling herself again. There’s a real desperation to her character, so lost after the death of her husband, with no family she would want to be close to or anyone she wants to connect with. When she finds Bernie, she actually feels something, and it’s sad that that’s her downfall. Matthew McConaughey rounds out the cast as D.A. Danny Buck, an arrogant, narcissistic lawman who nevertheless comes across as a voice of reason when he’s baffled by townsfolk who either refuse to believe Bernie committed the crime or think that Marjorie had it coming to her, anyway. McConaughey got his big break as the sleazy Wooderson in Linklater’s Dazed and Confused almost 20 years ago, and here he gives his best performance since…well, since Dazed and Confused. He’s at once a fool worth laughing at and possibly the only wise person in the film.

Bernie is one cup mockumentary with a pinch of documentary and a heapin’ helpin’ of black comedy that you’re never quite sure whether to find hilarious or disturbing. The end result is a fascinating, very funny film that will leave you ruminating on the titular character and his actions for days after. It’s a reminder of just what a fresh, unusual voice Linklater can be.