"She's been with us on The Hill for nearly a year now," Jo explained. "Came to us from anti-corruption. AC-12. Fitted in perfectly. Then we got our current case,".

"Which is what?".

"A woman in her thirties found dumped in some park. She'd been beaten to death. No sign of being raped. The member of the public who found the body might have disturbed him as he saw someone running from the scene. She hadn't been long dead,".

"Any potential suspects?".

"All her nearest and dearest were checked out and have alibi's. It is looking increasingly likely it was just a case of the victim being in the wrong place at the wrong time,".

"Quite rare. Murders are usually carried out be someone known to the victim,".

"I know. We got a psychological profile of the perpetrator. There is some sort of fetish with underwear. The victim's was taken from her and she was found naked with her hands bound,".

"I hate to ask but was DI Fleming found in similar circumstances?" Derek asked. Jo nodded. "Are you thinking it's the same person?". Jo nodded again. Derek realised they might be looking at a serial murderer.

"Kate has recently been the victim of a stalker," Jo explained. "It started not long after we got the case. Even at the scene of the first murder she had the feeling we were being watched. She had this hang up as well because our victim looked strikingly similar to Kate. Our suspect seems to like a particular type of victim".

"Which is what?".

"Single woman mid to late thirties. Slim build. Short close cropped hair," Jo described.

"What has this stalker been doing?" Derek asked.

"It started off with typed letters through the post. Not hand delivered. Each with differing post marks so we've no idea where he lives," Jo replied. "She came to me with them after she realised they weren't going to stop,".

"You read them?".

Jo nodded. "Talked about how much he was in love with her at first. Some even included a picture of his genitalia. Then they got a lot more graphic. Quite frightening really. A lot of BDSM stuff in them,".

"Is this stalker our suspect?" Derek proposed. "Acting out his fantasies,".

"It looks that way," Jo agreed.

"You say it 'started out with letters'. What has happened since then?".

"Kate constantly felt like he was watching her. Even in her home. She became almost a recluse. Afraid to go out and socialise,".

"You have evidence of this?".

"He certainly knew a lot about her. Presents were being sent to MIT on days she worked there. Like he knew her rota pattern," Jo explained.

Derek made a note. It was a horrible thought but he was going to have to investigate Kate's friends and colleagues.

"Then she found out he'd been in her flat," Jo revealed.

Flash back

"Come on, Kate," Jo said. "If anyone needs a drink it's you," she pointed out. They were in Jo's office and the DCI was trying to get Kate to join the rest of her team for a drink to celebrate the end of another working week.

"I know," Kate replied. "I'm just not in the mood," she explained. Her current situation with her rather persistent stalker was affecting her mood, bringing it down.

"Then you need your mates to cheer you up," Jo reasoned. The whole of MIT had seen how the stalker was affecting Kate and they'd asked Jo to see if she could succeed in getting Kate to join them for a drink after she had declined each of them earlier in the day. "Look, Kate," Jo said. "Come out. You say you feel like he's watching you at home. Better be out with friends than by yourself then. I'll get Chris to walk you home and make sure you're safe at the end of the evening,".

Kate thought about Jo's offer. She really wanted to go out. She shouldn't let this stalker deprive her of her usual life. "Ok," she found herself saying. "I'll come out for a drink," she conceded.

Jo smiled. Job done. She was happy that the whole of MIT headed to the pub after hours for the first time in a couple of weeks.

Jo could see Kate trying to put on a happy facade for the rest of the team, but as the evening wore on it became more tiresome until eventually Kate wasn't really joining in with the conversation much. Just sat in her own little world.

"BOO!" A shout was heard that shocked Jo out of her skin. Looking around she saw that a man who knew Kate had decided to surprise her which didn't go down well.

"You fucking idiot!" Kate screamed at him. The man looked shocked. Jo saw the two look at each other. Realising they were the centre of everyone's attention in the pub, Kate scarpered.

Jo made to go after Kate but was stopped by the new comer. "I'll go," he informed her, realising he'd made the error and should be the one to correct it.

End of flashback

"Who was this person?" Derek asked.

"Turns out it was her old partner from AC-12. Steve...Arnold or something," Jo remembered, searching her memory for the correct name. "Kate reappeared a little later with him and introduced us. They had obviously made up outside and Kate was actually much happier with him around," Jo recounted. "Steve saw her home in the end. I got a call from Kate later that evening to inform me she would be staying with him at his flat for a little while. They had found that her stalker had been in her bedroom when they had reached Kate's. Been through all her underwear,".

"Was she still at his?" Derek asked. This Steve person was someone he needed to speak to urgently.

"I don't know," Jo replied. "She was on Friday,".

"Why hasn't he reported her missing then?" Derek pondered out loud. Bit strange. Maybe it would become clear when he spoke to him.

The meeting finished shortly afterwards and Derek headed off. Finding his phone he called his DI. "We've got a rather interesting case," Derek informed him when he answered.