D.S. Sykes was the police detective tipped off by Jim McGinn about a plot to kill Myra McQueen. Sykes led a team of officers that stormed 26 Leigh Road and arrested Trevor Royle who was inside alone. However, Trevor was released two days later due to a lack of evidence. After Myra's 'death', Sykes questioned her son-in-law Paul Browning who confessed to killing her and Lynsey Nolan (having been acquitted in December 2012), and attempting to kill Cindy Cunningham and Mercedes McQueen. The next day, Sinead O'Connor revealed to Sykes that she was an informant for missing detective Richie Trent so Sykes questioned her.
In October 2013, Sykes was called to a body discovered in nearby woodlands, later identified as D.C. Trent. The next day, Sykes questioned Sinead for a second time, this time using scare tactics until D.I. Sam Lomax intervened and took over the case. In November 2013, Sykes and Lomax re-opened the investigation into the murder of Anna Blake at the request of her son Dodger Savage, with Sam noticing Will disguised as a construction worker entering Anna's ward shortly before her murder. Unable to find him at his flat, the pair led a desperate search and eventually found him at Anna's manor shortly before grabbed Dodger and leapt from the roof.
In December 2013, Sykes led the search for Sienna Blake, who had kidnapped Tom Cunningham. Dodger found her inside Roscoe's Motor Maintenance, having taken Tom, Charlie Dean and Oscar Osborne hostage and attempted to gas them with Frankie Osborne's car. As the police surrounded the building, Sienna reversed through the door but ended up crashing the car and was arrested. In January 2014, Sykes questioned Carmel Valentine over the theft of a dollshouse from a toy store a week earlier, only for Carmel to discover that her cousin Theresa McQueen was the true culprit. Later in the month, he questioned Freddie Roscoe over a car booked in for repairs in his garage, which was involved in a hit-and-run.
In March 2014, Sykes visited Fraser Black after hearing a report that he was in possession of a shipment of drugs and searched Fraser's car boot. Two days later, Fraser's burnt-out car was discovered in a field with the body of D.S. Sykes in the boot.