I don't own Midsomer Murders, but to me, The Creeper was among the best episodes as well as Murder on St. Malley's Day there was.
The End of the Creeper.
In a way he had been delighted, ever since he had become a DCI for Causton CID, all he seemed to have done was just blunder from one murder after another without any kind of end. It was good to finally encounter a burglar, especially one like the Creeper.
While Tom wasn't entirely sure about the nickname for the burglar, made up just so then the newspapers could sell more papers, he had the feeling if anyone could be so creepy, it would be Tallis Cox.
Tom had liked her, and he knew he had her respect as well. The young girl was highly intelligent, daring, and courageous; she might have been a bored young woman, frustrated with her family at times, but Tallis had proven herself to be a capable burglar who planned and acted out her burglaries meticulously.
Some other burglar might have been content letting others believe they were murderers, but not Tallis. Tallis had gone out of her way to break into Tom's own home and make it clear to him she'd had nothing to do with it. In any case, it wasn't that hard for him to discover the murderer. He'd had pure doubts about the Creeper being the murderer.
Tom had been a police officer for a long time. He knew only too well how everyone had the capacity to kill, but no matter what, he had doubts the person under the Creeper guise would commit murder unless they'd planned out the details meticulously. Besides, the Creeper had had dozens of opportunities to become a murderer for real, but Tallis had not shown any signs of violence in her crimes.
While it wasn't really funny, well it was, Tom had been amazed by the guile and audacity behind Tallis's burglaries, especially the one Chief Constable Lovell's burglary. It was their own fault since Mrs Lovell had the habit of leaving the back door open for long periods - it was obvious Tallis had found that little habit, and she'd taken advantage of it. But she hadn't murdered anyone there.
When he had found that fox hair and how he'd seen the little fox Tallis was keeping hidden in the woods on the grounds of her family home, Tom had been impressed by the young woman's love of animals and her commitment to them. But as the Creeper, she had made a mistake. She had accidentally brought a fox hair into his home, and when he found out after the hair had been examined, Tom had known who was under the mask Joyce had described.
Tom could have confronted Tallis and arrested her. But he didn't. To him the young woman was not your a-typical burglar; she had a different drive and her earlier compassion had been the most impressive feature. Tallis had broken the law, yes, but she hadn't done it for the wrong reasons and besides he had genuinely liked her.
To Causton the Creeper had disappeared as fast as 'he' had come, but if Tallis did show up again somewhere else, and he had no doubt she would, well, he would say nothing.