Steve looked at Derek and James. "A neighbour did this?" Steve asked. Kate nodded happy he had finally understood her. Trust Steve to get it.

"Which one?" James asked Kate, excited they were making progress. "There's a lot of people live in that building,". It was going to be very difficult and time consuming to visit everyone.

"Sss...Sss...," was all she could say. The word very difficult to pronounce and she was getting tired.

"Has she got a neighbour starting with the letter S?" James asked Steve as he looked through his pocketbook searching for someone that did.

Steve was desperately trying to recall all the names that Kate had told him when she tried to get his attention by tapping on his chest a couple of times. Steve stopped and looked at her and it gave her an idea.

She tapped his chest, twenty two times. "Twenty two?". Kate nodded. He'd counted correctly. "What's the twenty second letter of the alphabet?" Steve asked James, who started counting on his fingers.

Kate shook her head. They were going down the wrong path. "Not the alphabet?" Steve checked. She tapped twenty two times again on Steve's chest. A light went off in his head. "Flat 22?". Kate nodded. "It's a fucking next door neighbour," Steve declared. "Kate lives at number 20,".

James looked through his pocketbook. It was the same neighbour who had seen Steve and Kate together at her flat. "That would be a Mr Xander -".

"I told you I was right to be suspicious about him!" Steve interrupted as he talked to Kate, feeling totally justified in his total dislike of the man.

"Sor...re," Kate answered.

"You shouldn't be apologising," Steve said as he kissed the top of her head. "He should be,".

"I think it's time we go and pay Mr Xander another visit, don't you?" Derek asked James. James nodded.

"I'll come too," Steve said as he jumped off Kate's bed. He couldn't wait to get his hands on the bastard.

Derek put a hand out to stop Steve in his tracks. "Not this time," he replied. "This isn't AC-12. Let us do our job," he told Steve. He pointed at Kate. "Your job is to stay here and keep our star witness company. After all I think I just heard you promise her you wouldn't leave her again,".

"I've really let you down, Guv," James said as he ascended the stairs in Kate's apartment building with DCI Wheeler. "I fucked up with Steve and I'm the one who interviewed this person originally and didn't follow up on his statement," he said. "I'm sorry,".

"He's been hiding in plain sight," Wheeler advised. "He's been fooling us all for a long time," he continued. "Apology accepted,".

"How do we play this," Booth asked as they neared the correct floor.

"Gently," replied Wheeler. "Just a follow up call. Give him a false sense of security,".

"And uniform are downstairs in case he makes a run for it,".

"Exactly," replied Wheeler.

They stopped in front of Number 22. Kate's front door was behind them, now closed and covered in police tape. Booth gave it a gentle knock.

"Who's there?" Came a shout from inside.

"Police," replied James. "We were wondering if we could ask you a few more questions?".

Derek and James waited for the door to be opened. It took an age but just as James was wondering whether he should break down the door or not, it opened a tiny crack for the occupant to show his face.

James' nose was met with the most awful smell and he had to force himself not to gag. Something putrid was in the flat. Looking at the owner however, the smell might have been originating from him. He looked awful. Pale. A sweaty sheen across his forehead. His eyes looked vacant as he took in the two police officers before him. "Are you alright?" James asked.

"Yeah," he said. "What's this about?" he asked, keen to get this visit over so he could be left alone.

Derek nodded at James. "Xander Furlong I am arresting you for the assault and attempted-" was all James could say before their suspect collapsed to the floor.

"You in here, Guv?" James hollered a little later. He was in the hallway of Flat 22 searching for his SIO.

After their suspect had collapsed, they had ended up calling for an ambulance and the paramedics had just taken him away with a police escort as he was still under arrest.

Derek stuck his head out of a room in the flat. "He going to make it?" he asked James.

"Yes. They think he has caught an infection from something," James informed his boss. "Something sure smelt bad on him," he added.

"Come and have a look at this," Derek said as he retreated back in to the room he was in and James followed.

He was shocked as he stepped inside. Photos of Kate filled the walls. Thousands of them. There was no paint or wallpaper to be seen as there were so many. Black and white and in colour. Kate outside. Kate in her flat. Having a meal. Doing chores. Watching TV. Getting dressed. Sleeping.

"Fuck," said James. This guy was totally obsessed by the female police officer. "Guess we found the stalker,".

"Looks like it," the DCI agreed. He moved and James saw a video screen on a table that appeared to show some low budget porn film. The woman astride the man as she assumed the dominant position on top. He pressed a button and it quickly became apparent it was footage of Steve and Kate having sex as their gasps and non sensical utterings filled the room. Embarrassed, James quickly pressed pause. Whilst the audio stopped immediately, unfortunately the screen paused on Kate with a look of total bliss on her face as she neared completion.

"Definitely consensual I hope you would agree," Derek said rather tongue-in-cheek.

By the side of the screen was hundreds of photographs of Steve and Kate in bed together that had been printed from the video tape. They were either sleeping, talking or in the act of sex. Some had been doctored quite disturbingly with Steve's head being covered with the stalker's. "Think Steve was right about the trigger point for the violence," he added, pointing to the photos. James blushed.

"Yeah," he agreed. "Wanted Kate for himself and then realised he couldn't. How long has he been doing this?".

"A few months at least by the looks of it," Derek said. "Look at this," he urged James as he held out a photo for him to study. Another unknown woman filled the picture. She was mid workout on a treadmill in a gym on the local high street and had a look of Kate about her.

"Next target?" James theorised.

"I would say so," Derek said, for once agreeing with him. It looked as though they had caught this menace just in time before he struck again.