"That's all well and good, but I don't understand what this has to do with me. I thought I wasn't allowed to help you anymore."

Lestrade shrugged awkwardly, and handed Sherlock the opened letter on the desk. Sherlock looked at him questioningly, and Donovan explained.

"Got your name in it, freak. It was written to you. It came with the body, blood splatters and all. Doesn't make any sense to us, but to a genius like you it should be child's play."

Sherlock frowned at her, and turned his attention back to the letter. He sat on the edge of the desk as he read it. John read it over his shoulder, a look of pure confusion etched on his features. Sherlock's eyes darted back and forth as he read the lines, and his eyebrows slowly contracted. It made no sense. He felt as if a part of it made sense, almost as if he recognised it. But he could make no connections. He peered at the handwriting, but it was faded as if with age and dust, which made it hard to decipher. It looked familiar. He didn't recognise the signature either.

"I don't know," he admitted slowly, as he put the letter down, "It doesn't make any sense to me."

"see?" Donovan whispered to Lestrade, who shushed her with a hand gesture. Sherlock didn't respond, going over the signature in his head.

"Do you know anything about the writer?" he asked Lestrade, "Aside from the obvious, I mean."

Lestrade rolled his eyes and gestured for him to continue. Sherlock leant back and assembled his thoughts.

"Judging by the amount of staining, I'd say that it was writ-"

"Got it!" cried Anderson from outside the door, and he barrelled into the room, managing to purposely knock Sherlock off balance as he did so. He threw down the laptop triumphantly. "Got a picture of him and everything. Well, it's him when he was about forty, which seems about fifteen years ago, but still. We've also got a criminal record, which might interest you."

"What does it say?" Sherlock asked, regaining his balance with only the smallest of evil glances in Anderson's direction and squinting at the screen from where he was standing. He couldn't make out the face.

"Well I don't know, do I?" Anderson said hotly, "I haven't read it. I know you can probably deduce everything from one glance, but we're not all freaks like you."

Sherlock raised an eyebrow and spun the laptop to face him, and glanced uninterestedly at the picture. He didn't need to know the face, he could work it all out as long as –

He stopped dead. His face blared shock at the other four. He shook his head as if to ward off a wasp, face drained of all scarce colour, "No." he said incredulously, "what?"

John looked on in some confusion, "Sherlock? What's the…" Sherlock put his face in his hands momentarily, and John looked at the photo, not recognising the occupant. "Who the hell is that?"

Donovan was watching Sherlock in obvious confusion, "It's just a… man, we don't know. He changed his name a few times, and we can't find the original. But that's definitely him. Definitely the guy that wrote the letter."

John looked at her in confusion, "What, you can't find his name at all? No paperwork? Birth certificate? Anything?"

"All wiped," She replied, flexing her jaw, "And it isn't easy to do that sort of thing. Just, disappear for years. Not many people could pull it off." She looked pointedly at Sherlock, who glared at her.

"Don't rub it in, Donovan." He said in a low voice, then turned to Lestrade, "Read the rest. Bound to be something interesting." He finished in a neutral, unemotional voice. John looked at him in confusion, realising something was wrong.

"What?" he mouthed, but Sherlock shook his head in reply. John frowned, and turned back to Lestrade, who was scrolling down the page.

"He went to jail under… oh, that name was wiped too. Hmm. Urrr… here it is, for abusing his children. Apparent history of violence, and could possibly have been… abusing them… for years before they summoned up the courage to tell someone." He winced at the details, and then bit his lip, "One of the kids… no, must have been a teenager – anyway, one of the kids fitted a camera into a corner. Filmed the whole thing."

"Fitted a camera?" Anderson said in disbelief, and Lestrade shrugged.

"Actually, the video's here. I should be able to access it…" Lestrade pursed his lips as he typed furiously. Sherlock looked slightly sick. The DI cried aloud in triumph, and the video started playing.

For a while, nothing much happened. Donovan and Anderson exchanged looks, and then glanced at Sherlock, who had assumed his customary 'I'm so smart nothing you do or say will do anything to alleviate my boredom' face.

Finally, something on the screen moved. The bedroom – for it was a bedroom – was suddenly lit, and a boy no more than twelve or thirteen tore into the room.

"We're leaving!" he was shouting, "Me and mum, we're leaving, and you're not coming!"

The boy was hysterical, and was shoving pieces of clothing into a large suitcase, "You're not gonna hurt us anymore!"

Then the door was wrenched back open, and the man in the photograph entered. He was tall, and he was smoking with rage. They could even see it through the fuzzy, low quality camera. Donovan's breath hitched.

"You going to fight me, you little freak?" Roared the man, as he grabbed the little boy bodily and held him against the wall, "you think I won't make you scream, right here for speaking to me like that?"

The boy's little fingers were plucking at the man's thick wrist, choking and sobbing, "I'm sorry daddy, I didn't mean it, I didn't mean it, I'm sorry, I won't do it again daddy-"

Anderson put a hand over his mouth as the father shook the boy like a ragdoll. The boy was crying his eyes out.

"You're sorry, huh, you little freak? You're sorry? No, now you're sorry!" he roared, and thumped the boy's head against the wall, "You little freak! Now you're sorry!"

"Daddy!" scream the boy, holding his head in his hands, and trying to kick the older man, "Daddy, stop, you're hurting me daddy-"

Lestrade stopped the video, and covered his head in his hands. Anderson looked sick. John stared at the screen, pale and silent. Donovan had a tear on her cheek, and her hand was pressed so firmly over her lips it look as if she were close to vomiting.

"That… poor kid." She whispered, taking her hand away from her mouth.

Sherlock couldn't help it. A laugh burst out of him.

Donovan turned on him, murder in her eyes, as he chuckled away behind her.

"What are you laughing at?" she asked in a dangerous voice. Sherlock smiled hugely, still laughing under his breath.

"You," he choked, "I'm laughing at you. It's so ironic. Oh," he said, imitating her, "that poor boy."

Sally slapped him, hard, "That little kid was probably scarred for life!" she screamed, "How can you just sit there, and laugh? You bastard, you utter bastard!"

Sherlock raised an eyebrow sarcastically, "Yes, he probably was. And I bet he felt absolutely horrible every time someone called him a freak."

"If he even survived!" Sally shrieked, "Do you actually have no feelings at all? Have you no… can you not comprehend, the pain that poor kid must have gone through, for years if he made it past thirteen?"

"Fifteen," Lestrade corrected her, reading more of the page. Anderson turned to Sherlock as well. He was staring at him as if seeing him from a new light.

"You really are a psychopath, aren't you?" he said; distaste radiating from him. John looked at Sherlock with a frown in his forehead.

"No, Sally, the kid survived," Lestrade said, reading out the rest of the information, "He had a broken skull… trauma… ah, here," he read out a passage, "The son was taken to hospital and took extensive rehabilitation courses for… years of similar abuse…" Sally looked pointedly at Sherlock, and mouthed freak and psychopath at him, "The father was taken to court and sentenced… um… the youngest son, the most abused and most injured, mm, that must be the one in the video… the young son was released, but carried 'heavy mental scars', whatever that means. The older son moved on, the mother was committed to a mental hospital, and the eldest son took custody of the younger once he was released. Umm… here, the younger son, who's skull was split in the last argument, one Sh-"

He stopped, and went pure white. Donovan was about to question him, but he swallowed and turned to face Sherlock.

"-erlock Holmes…" he continued, staring at his friend in shock. Donovan's mouth dropped. Anderson stumbled on his own feet, and John looked as if he were going to collapse. Sherlock rolled his eyes and leaned back.

"And the light dawns," he said sarcastically, throwing his arms out in a large sweeping gesture, "That took you far too long to work out." He sat down in front of the computer, and tried to ignore the stares from the other four. Donovan looked like she was going to cry. Sherlock ignored all of them, as he searched the site for more information about his father's recent movements.

Anderson was standing across from Sherlock, and his throat was working as if the words he didn't want to say were forcing their way out. Lestrade put his hand on Sherlock's forearm.

"Jesus," he said, shaking his head as if to rid himself of the image of his friend screaming his head off, "Jesus…"

Sherlock smiled too himself, cool as ever, except for a tremble. But if anyone knew him (and he could only put John in this category) they would know he was trying not to let out his emotions. His tears. He wasn't a one for crying. He never had been. But he couldn't help it. He could feel his father's hand at his neck, and he swallowed defensively. The sound echoed in the silent room.

Anderson watched him in absolute disbelief. Sherlock's face was perfectly impassive, he might almost have passed as nonchalant. But, Anderson noticed, his hand was shaking. Violently.

"Oh for god's sake," Sherlock said suddenly, "I can't take this." He slammed the laptop closed and shoved he way out of the door, "Come on John." he scowled, "I've got better things to do than this." John hurried out after him, and shot Lestrade a befuddled look, before the door swung shut behind them.

"Oh my god," Anderson finally allowed himself to say, "Oh my god."

Sally said nothing, and let her tears do the talking.