The BBC has defended Crimewatch's new format as "necessary" after viewers slammed the programme for using a historic real-life murder case as a "cliffhanger".
Fans of the show expressed their disappointment as Monday night's episode ended on the retelling of the case of Melanie Road, who was raped and killed in 1984 at the age of 17.
The case was reopened years later and, thanks to the advancements in DNA-testing techniques, the murderer was finally caught in 2015 and given a life sentence earlier this year.
The episode finished with viewers being prompted to tune in next week to find out how the case was solved, which encouraged some to take to Twitter to compare the series to a "soap opera".
A BBC spokesman told the Press Association: "Crimewatch worked closely with the police on this item which was made with the cooperation of Melanie Road's family. The story of Melanie's brutal murder and how detectives eventually caught her killer spanned decades, involving hundreds of police officers and multiple investigation teams.
"To do full justice to Melanie's story it was necessary to tell it across two programmes."
They added: "With Crimewatch now airing in a weekly format it was important to inform viewers that the conclusion of the case would be shown the following week.
"How They Caught items are useful in reassuring viewers that despite all the crime featured on the programme, criminals are caught and justice is served."
The BBC's long-running crime-solving programme aired with a revamped series which will be shown on a weekly basis for the first time, with Jeremy Vine and Tina Daheley as the hosts.
Viewers took to Twitter to air their upset over the teaser-style ending ahead of next week's episode.
One wrote on the social networking site: "Disgusted at #Crimewatch, a girl's rape and murder being treated like a soap opera cliffhanger, shame on you."
Another added: "'Next week?' Since when did #Crimewatch become a soap opera? A cliffhanger about a real life case? Really?"
One viewer described it as "disrespectful" adding that "it's a real show, it's not a TV drama!".