DS Shields was the detective who, alongside DC Flanagan, oversaw the investigation into Alex Moss's murder in 2013.
Following Katie Addyman's anonymous tip off that there was a body buried at Home Fields Glamping Site, Shields and colleague DC Flanagan appeared at Home Farm to speak to Declan Macey. A few days later, workman Thomas Hillam informed the police that had Declan paid him to cover up a suspicious object that was found whilst digging the foundations of the glamping site. Hillam showed the police were to dig and subsequently they uncovered human remains. Declan was arrested for perverting the course of justice and Shields and Flanagan interrogated him about the body as well as Katie's sudden disappearance. The body was later identified as Alex Moss.
After punching Declan, Adam Barton was arrested for assault. Whilst being questioned over the assault, Shields and Flanagan took over the interview and interrogated Adam about Alex's murder, suggesting that Alex's relationship with Adam's mother Moira could be his motive. The police later found a glove covered in Adam's DNA that Cameron Murray planted near to where Alex's body was buried. Adam soon discovered one of his work gloves was missing and realised he was being set up. Whilst the police searched Butlers Farm, Moira's boyfriend Cain Dingle distracted the police officers which allowed Adam to escape and go on the run.
A few days later, Chas and Debbie Dingle went to the police as they suspected Cameron was responsible for Chas' sister Gennie Walker's death and believed he may also be responsible for Alex's murder. Shields and Flanagan questioned the women but as they didn't have enough evidence to arrest Cameron, they suggested putting hidden cameras in Debbie's house to get a confession. Although reluctant, Debbie agreed. After Cameron referenced killing Carl King out of reach of the cameras, Debbie insisted on wearing a wire to catch his confession again. Shields and Flanagan were against the idea but went ahead with it. Debbie was able to get now suspicious Cameron to confess but told him about the wire and cameras and as a result Cameron locked all the doors and held Debbie hostage. Debbie managed to escape and Cameron was arrested.