Hain explains to Carol his own position fifteen years earlier and how he was dropped from the case - and even briefly in the frame - because he was a client of Sally, whom he loved. He used Cleo's,the massage parlour where Sally worked, to gain information from other working girls like Rachel and suspected another policeman, Oliver, of having shady dealings with Tony Phillips, the man behind Cleo's, though Oliver explained he was working under cover, to expose fraud. Hain was subsequently given early retirement, though he tells Carol that he has recently seen Whittaker, a man who wanted to photograph her when she was a child and was himself, for a while, a murder suspect. She decides to go under cover herself at the massage parlour.
—don @ minifie-1