The Bill - Season 15 Episode 35 Push It
Overview: Jessica Orton is brought in for questioning, but is released without charge. When she returns home, PC Santini is waiting for her, desperate to know if she grassed him up. They fight, and Santini hits Jessica, knocking her down the stairs and killing her. Realising her house is being watched, he escapes out the back. Vicki Hagen finds a set of keys under Santini's bed which she brings to the station to return to him.