Book him, Danno – but not until the audience decides: Viewers get the chance to pick the killer in 'Hawaii Five-0'

Whodunnit: the current cast, (CBS)

Television audiences are, by now, accustomed to the notion of voting to decide the outcome of a reality show. What they may not be so prepared for is the opportunity to pick the killer in their favourite detective drama. Now, in a first for a US prime-time drama, the CBS network is offering viewers of its revival of Hawaii Five-0 the chance to choose the ending of an episode. On 14 January, fans of the series will be invited to vote, via CBS.com or Twitter, on which of three suspects committed the murder being investigated by its heroes.

Hawaii Five-0, a so-called "reimagining" of the classic 1970s series, is now in its third season on CBS. An action-packed police procedural starring Scott Caan as Danno (of "Book him, Danno" fame), it follows a small crack squad of investigators tasked with thwarting the titular archipelago's most serious crimes. During the episode in question, the team is due to investigate the murder of an Oahu State University professor, and three suspects are in the frame: the professor's boss, his teaching assistant and a student he had sent down for cheating.

All three of the potential villains will have their motives exposed in the first half of the broadcast, at which point viewers will be instructed to go online and choose #TheBoss, #TheTA or #TheStudent. The ballot will be settled during the episode, which will conclude with the capture of whichever suspect turns out to be the most – or least – popular. After the episode's broadcast, all three endings will be available to watch at the CBS website.

"I've always felt the most fun aspect of watching a mystery is trying to figure out whodunnit," the show's executive producer, Peter Lenkov, told The Hollywood Reporter. "Now Hawaii Five-0 viewers will get the chance to tell us who they think committed the crime, and we will listen. I love that our dedicated and attentive fans will play a part in resolving our story."

Might choosing the ending not remove some of its thrill? Maybe, says Brian Lowry, a TV critic and columnist for Variety. "When shows get into their later seasons, especially if they're procedural, it's not unusual to spike them with some sort of gimmick."

Though this televisual experiment is the first of its kind, others have tried similar interactive pranks in the past. In 2001, Chuck Lorre, the sitcom super-producer behind Two and a Half Men and The Big Bang Theory, produced a pilot for Fox entitled Nathan's Choice. In each episode, the title character – a twentysomething graduate played by J D Walsh – would be faced with a dilemma, which viewers would be invited to resolve by voting for one of two paths of action midway through the broadcast. Two alternative endings would be shot for every episode, with the less popular one shown when the programme was repeated later. Fox, however, did not commission the series, and the pilot was never aired.

CBS is keen to trumpet its engagement with the new world of social media. Last week, the network also unveiled a new app for the iPad called CBS Connect, which is designed to link users together via Twitter, Facebook et al during the broadcast of their favourite shows. Connect can identify what each user is watching and tailor its services to sync with the programme – even if the episode is being watched on a DVR recording. Currently, the app works only with the police procedurals CSI, NCIS: Los Angeles and Hawaii Five-0, but it is expected to roll out to other series in due course.

"Everybody is feeling their way in this area," says Mr Lowry. "The networks' infatuation with social media is, at this point, more window-dressing than something that actually draws lots of viewers to shows. But you don't want to be the one idiot who's not jumping into the pool when it's getting hotter outside."