The worst thing for Mycroft was the unexplainable sense of loss. Unexplainable because he knew Sherlock wasn't dead. He had never liked his brother. But somewhere deep inside he felt a panging sense of loss that was ripping him apart, purely because he had never experienced it before and didn't know what to do.
"Sir. We have an urgent message from one Irene Adler." Jonathan announced from the doorway, handing Mycroft a sheet of paper. Jonathan was a good boy. Been on the job for a week. Mycroft didn't think he was right for the job. He'd ask someone to tell him nicely.
"Yes, thank you Jonathan." the boy walked away, smiling.
'''I send my regards. Me and Sherlock could have been friends,''' Mycroft snorted at this, "But circumstances intervened. I hope John is OK. Irene x.'''Mycroft sighed. Irene was annoying.
He threw the papers across his desk, rubbing his fingers in his eyes. He hadn't slept last night. Or the night before. Or the night before. He hadn't eaten since yesterday breakfast.
"Sherlock isn't dead you idiot!" he yelled at himself, before quickly composing himself. He mustn't seem upset, people will think less of him. And his brother WAS NOT DEAD.
"Sir." it was Jonathan again. Mycroft sighed.
"DI Lestrade to see you, sir."
Lestrade walked in, red-faced and shivering from the cold.
"You need to come and see this." he said, waiting for Mycroft to move. He didn't.
"I am busy. If it's not a matter of national importance, I cannot spare my time for it."
Lestrade sighed.
"If I said it was about Sherlock, would you come?"
Mycroft stiffened. He paused, then stood up, walking over the Lestrade and nodding at the door, waiting for him to go so he could follow.
Lestrade smiled.

"There." Lestrade pointed to the pink graffitti on the wall, glowing against the dark background. Mycroft frowned.
"Do you know who did this?"
"No. I don't think it was John if that's what you're thinking." Lestrade said. Mycroft shook his head.
"No, no... I just wanted to pull them in for questioning to see if they knew if Sherlock was alive." of course, he couldn't tell Lestrade he was alive. Not yet.
"'I believe in Sherlock Holmes.', eh? What next?" Lestrade commented. Mycroft turned around and looked at the wall behind them.
"Maybe 'Richard Brook = FRAUD'?" Mycroft suggested, and Lestrade chuckled weakly.
"No, really. Look." Mycroft explained, leaning on his umbrella. Lestrade turned around and saw in blinding White paint the words:
Richard Brook = FRAUD
"Blimey." Lestrade muttered under his breath.
They stood there in silence for a while, staring at each message in turn. Whoever had put them there was not bad, in Lestrade's opinion. He'd let them go if they were caught. He knew that. They were merely standing up for what they believed in. And they believed in Sherlock.

Mycroft sat in his office, thinking about the graffitti. He could tell they were done by different people, but they were both experienced. There were no tags so they obviously didn't want to be recognised, or maybe they wanted all the attention on the message. The first message was done by a 21 year old male, 5.9" and a half. Mycroft was guessing Raz - him and Sherlock had always seemed to get on.
He was staring out the window, listening to his own thoughts when he noticed the writing. It was yellow paint this time, written on the wall exactly opposite his office. He knew it was meant for him. Because of it's position and because of what it said:
Don't stop believing.