He was halfway through his examination of the crime scene when something caught his attention.
Donovan was crouched in a corner, vainly trying to soothe a little girl who was rocking back and forth in a sort of frenzied panic. Memories of his own childhood stirred inside a dusty room of his mind palace, a room whose door he'd kept locked and bolted for ages.
"You're doing it wrong," he bluntly informed the sergeant, gesturing for her to move over. "Let me."
Donovan merely stared at him in disbelief. "Yeah, right. Because you're notoriously good with kids, aren't you, Freak?"
He ignored the sarcastic quip and kneeled behind the girl, his brow furrowed in his effort to remember the correct procedure. Gingerly he wrapped his arms around her and applied the right amount of pressure, just the way Mycroft used to do with him when they were kids.
The little girl slowly started to calm down, her back relaxing against his chest; only then he turned to Donovan.
"Sensory overload," he offered by way of an explanation. "Deep pressure stimulation usually helps."
"You mean she's autistic?"
"Asperger's, I would say. Take her somewhere quiet, where she can unwind a bit."
A softer look flickered across Donovan's features for a moment. "Thank you, Sherlock."
He smiled briefly, then dashed back to business.