When it comes to TV mysteries, short is sweet.

If you harbor any doubt, visit BBC America's "Broadchurch," a whodunit so compelling that its British run became the most tweeted-about program in the country's history.

The story takes place in an idyllic seaside town where you can't walk down Main Street without hailing every other person, where a grade-school soccer game is a major sporting event and a fender bender in front of the local pub is deemed high crime.

Then an 11-year-old boy's corpse washes up on the shore and every resident — the butcher, the baker, the candlestick maker — becomes a suspect.

In an American production, the characters would most likely be forced to wallow in grief and suspicion for at least 22 hours. But "Broadchurch" clocks in at a manageable eight hours with a definite — and delicious — conclusion.

The limited running time is partly the result of economics. Most producers working overseas can't gather the kind of money to back a longer run. But there's also the notion that many viewers won't invest the time in a case where the payoff seems to always be in the distant future.

"Any more than eight episodes would have been a huge ask for an audience watching a lot of trauma," said Jodie Whittaker, who plays the victim's mourning mother. "There's humor and other such wonderful moments in it, but the basis is the most unimaginable event, and I think eight hours serves that piece. To drag it on longer, it didn't need it."

The producers of AMC's "The Killing" learned the hard way the dangers of keeping a mystery in the unsolved files too long. The series' opening episode in 2011 drew 4.6 million viewers. But when the creative team opted not to point out the killer in the original 13 episodes, fans flew into a murderous rage. The second-season opener drew a disappointing 1.6 million people, and this summer's third-season premiere wasn't much better.

"When I'm watching, I'm going to commit and give my time to watch it," said Olivia Colman, who plays one of "Broadchurch's" dogged detectives. "If it's 24 hours' worth of material and I don't get a reward at the end, it annoys me. It annoys me enough to not want to very well watch the next one. I don't think I'm alone in that."

American television slowly seems to be coming around to that point of view, even though there's a built-in disincentive for producers — shorter seasons means it takes longer for series to get to the lucrative world of syndication.

CBS' summer sensation "Under the Dome" has been renewed for a second season, but it's clear there will be some solid answers by the end of the initial 13-episode run.

"Hostages," a CBS fall series in which viewers have to figure out why an FBI agent is trying to orchestrate the president's assassination, would normally have a 22-episode run, with installments being interrupted by repeats and sabbaticals. Instead, producers promise a lean, mean 15-episode run with no breaks.

"It's a real gift for us," said creator Jeffrey Nachmanoff. "It lets you shape an arc without having to stretch and tap dance."

The abbreviated approach is also appealing to in-demand actors. Fox would have never gotten Kevin Bacon for the nail-biting drama "The Following" if the brass had insisted on a traditional run instead of a 15-week run with zero repeats.

"A lot of actors don't want to commit to doing 22 episodes," said Jerry Bruckheimer, the uber-producer behind "Hostages," who snagged Toni Collette and Dylan McDermott for lead roles. "Shorter seasons give them a chance to go on and do a lot of other things. It broadens the talent pool."

McDermott learned the appeal of a shorter run with his experience on FX's "American Horror Story."

"You're getting the best of the best," he said. "There's no fat on these episodes. We'll have a midseason finale and we'll have a finale. There's no bull."

Meanwhile, Fox announced Thursday that it will produce an American version of "Broadchurch" to air in the 2014-15 season. Let's pray they wrap it up in less than 22 hours.

Neal.Justin@startribune.com • 612-673-7431 • Twitter: @NealJustin