ITV is bringing back hit cop drama Unforgotten for a fourth season.

The series, which is being developed in the U.S. for ABC by Josh Berman, Sony Pictures Television and BBC Worldwide Productions, has been handed a six-episode run following the success of the third season, which average 6M viewers an ep.

The Split’s Nicola Walker and Sanjeev Bhaskar (Goodness Gracious Me) return as two London detectives, who work together to solve cold case murders and disappearances. The first series explored the case of the death of a 16-year old schoolboy, the second investigated the murder of a political consultant and the current season looks at the killing of a schoolgirl who disappeared on New Year’s Eve.

Creator Chris Lang will write the episodes, which will be directed by Andy Wilson with Guy de Glanville as producer for Sally Haynes and Laura Mackie’s Mainstreet Pictures.

Lang told Deadline earlier this summer that he only wanted to bring it back if the whole team returned. “If I can get the team together, I have ideas, that’s never an issue, but it’s whether we can pull the same team together. There are very few shows on telly, if any, where you have the same director [Andy Wilson] for 18 hours and the same production team and editors. We all know what we’re working towards and to do another one, we’ve got to make it even better, which is quite a big ask.”

Sally Haynes and Laura Mackie serve as Executive Producers alongside Lang and the show which is distributed by BBC Worldwide, was recommissioned by ITV Head of Drama Polly Hill.

Chris Lang said, “I am so delighted to have been asked to make a fourth series of Unforgotten. The reaction to series three was better than I could ever have expected (with more people watching the last episode than any other in all three series) and I cannot wait to discover what lies ahead for Cassie and Sunny, and to create a whole new cast of characters for them to grapple with.”

Hill added, “We have been delighted with the reception of the first three series of Unforgotten and are thrilled to commission a fourth instalment. Chris Lang’s writing is incredibly powerful and his storytelling utterly compelling, so we have no doubt that the new case will have viewers gripped again.”