Cathy later struck up a friendship with fellow PC Polly Page, who had just returned to work from sick leave following an attempted suicide. While Polly was a good officer, caring compassionate and loyal, Cathy was the exact opposite so their friendship was more of an attraction of opposites with Cathy seizing opportunities to capitalise on Polly's vulnerability.
Her big opportunity came when Polly befriended Dr. Owen Preston, who was terminally ill with a brain tumour. His wife Mary had been killed in a hit and run and after gaining Polly's friendship, he took her under his wing. When Polly was financally struggling, the doctor allowed her to move in with him and Cathy kept her beady eye on the friendship. When Owen gave Polly his wife's ring as a present, Cathy tried to convince her that the relationship was turning into a romance, which Polly instantly denied. Polly was then shocked and horrified when Owen confided in her that due to his illness, he wanted to commit suicide. She accepted his wishes and chose to accompany him the next night when he put his plan into action. At Owen's wish, Polly handed him a syringe that he filled with morphine and injected into his arm. As soon as he was dead, the devastated Polly phoned Cathy and informed her of what had happened. Cathy told her to stay where she was until she arrived. Cathy arrived and persuaded Polly to lie in her statement by saying that she came back to his house and found Owen dead. Polly agreed, but tried to reveal the truth at Owen's funeral and Cathy had to stop her. Polly later got some shocking news when she learned that Owen had changed his will, leaving her £150,000. By now, Polly was in too deep to change her story and was able to move on with her life, including beginning a relationship with wealthy Fish and Chip shop owner Max Wyatt.
But however, everything was put at risk for Polly when Owen's nephew Josh Preston arrived at the station asking to see her. At first, Polly was pleased to see him but the questioning quickly turned to her possible role in his death. Josh was curious and suspicious about the expensive ring and the money that his uncle had left Polly and she inadvertantly let it slip that she was with Owen when he commited suicide. She then offered Josh the money saying she didn't want it, but he took that as a bribe for his silence and told Acting DI Samantha Nixon about what Polly told him, who removed the syringe from the property store and dusted it for Polly's prints. When Polly's prints were discovered on the syringe a month later, she was mistakenly arrested by the Murder Investigation Team and charged with murder. Cathy then used the situation to dig her claws into Max, who later proposed to her. Cathy proudly announced her engagement in the hopes that it would make Brandon jealous, but Brandon wasn't interested.
At Polly's trial, a team of her colleagues were determined to prove her innocence - Sgt Sheelagh Murphy, Sgt June Ackland and PC Tony Stamp, who were all called to the witness box. Cathy herself was called as a witness and was at first trying to prove that Polly was innocent, until Polly's defence announced Cathy's engagement to Max having seen them together before Cathy was called to the stand. Realising Cathy's true colours and intentions on their friendship, Polly stood up and told the whole truth including Cathy's involvement in the cover-up. Cathy was called to the stand once again and both crawled her way out and mislead the jury by accusing Polly of lying and betraying their friendship through a convincing and emotional yarn. In the climax of Cathy's evidence, Polly was found guilty of murder and sentenced to life imprisonment thus being dismissed from the Police Service.
Cathy later betrayed Polly even more by milking her newfound fame when she made a television appearance on GMTV, being interviewed by Lorraine Kelly about Polly's trial and supporting the verdict. The whole relief were disgusted with Cathy's behaviour and Superintendent Adam Okaro was so furious that he ordered her to take leave so she could consider putting in for a transfer.