According to Broadcast, the detective shows have already begun work on further episodes, although the deal has not been fully greenlit yet.
Earlier today, it was revealed that Brenda Blethyn's ITV1 crime drama Vera would be returning for a second run.
Kate Summerscale adaptation Whicher, which starred Paddy Considine and Peter Capaldi, picked up over 6 million viewers and ITV drama director Laura Mackie is apparently keen for it to return.
Meanwhile, producer Hat Trick is already working on the follow-up to two-part drama Case Sensitive, which starred Olivia Williams and Darren Boyd as DS Charlie Zailer and DC Simon Waterhouse.
> Read our Olivia Williams 'Case Sensitive' interview
> Read our Darren Boyd 'Case Sensitive' interview
> 'Mr Whicher' drama enchants nearly 6m