DS Andy Roper was the Detective Sergeant at Syndicate 9. Presented as a smartly dressed, professional officer, he helped Gill Murray with the workload, and he also gave orders to the rest of the team. Andy had once been in a relationship with Janet Scott, and even when they were separated and they both got married, he still nursed a crush on her. In the first episode during Gill's briefing, he admired her legs.
In the second series Andy's character darkened when Janet's marriage with Adrian started fracturing because Dorothy, Janet's mother, was living at their home, and she was pushing Adrians' patience, and Janet lost it with him because he wasn't making an effort. Janet and Andy's relationship was rekindled, but Andy became too clingy towards Janet, and so she broke it off with him by visiting him at his home. He was truly upset and was even more upset when Janet admitted that she'd told Rachel, whom Andy considered to be an airhead. He was also rude towards Rachel afterhours in a pub when Syndicate 9 was investigating a racial murder, and he even demeaned her in public and in the office. At the time Janet was under enough stress questioning Geoff Hastings. When the two female officers left the pub, they left him alone.
Later Andy used his positon as Detective Sergeant to force Janet to do demeaning tasks rather than be part of an investigation, and so after she'd been called away to speak to someone during the case in question, he hassled her and it ended up as a shouting match. Gill spoke to the pair of them, and it was revealed to Janet that Andy had been married once, something she hadn't even known, let alone the fact it had broken down. As soon the revelation came out, Andy appeared to revert to his original persona - that of a professional police officer who respected Janet.
It didn't last because Andy used a vital phone call from the coroner who wanted to arrange an appointment with Gill to punish and discredit Janet - he told her the coroner was free to say the next day was perfect, but in Gill's company he said it was during the day of the call, so Gill was humiliated. Unfortunately for the pair of them, Gill had reached the end of her patience - she warned them both that one of them would soon be leaving the syndicate. Eventually it came out that Mitch had overheard the phone call, and came forward, proving that Andy had lied. Andy was later told by Gill to leave. The last any of Syndicate 9 saw of him, he was taking his things in a box, and none of them said a word, indicating that he was either unpopular or that his lie about Janet had circulated.