Silent Witness: Remembrance (Part 1 of 2)

Feature-length episode. The body of 20 year-old Lorna Katz is discovered drifting in the River Lea, with evidence suggesting she was tied up somewhere before she floated downstream. However, the death takes on an ever-more sinister significance when the team discovers that Lorna was the best friend of Ruth Tresize, a teenager who disappeared three years previously, with the missing girl's mother Ali becoming fixated on Nikki for information, convinced that the two incidents are connected