The Unexpected Arrival 3 (Parent!Lock)

"You can't bring Hamish in here!" Lestrade strode over to John, Sherlock and Hamish, "I'm breaking all the rules letting you both in here! This is a crime scene, not a playground."
"Uh, shall we wait outside?" John asked nervously, hugging Hamish closer to him instinctively.
"No no no, that shan't be necessary." Sherlock waved his hand in dismissal as he held the tape up for John to duck under.
"Sherlock, I can't let you take the child inside!"
"Either you let my son in, or we don't come in at all."
"Sherlock!" Lestrade protested, crossing his arms, however still allowing the three boys to enter. "Three minutes!" He called after them.
    "Right, Hamish." Sherlock reached over and took the child from John's arms, "Tell us what you see." The body lay on the pavement, the man's white t-shirt saturated in blood. His face was peaceful, he almost looked asleep if it weren't for the stab wound in his chest.
"John," Hamish pointed to the man, "John, put... put plaster on it." The elder man laughed,
"I'm sorry Hamish, a plaster won't make him better!" Sherlock pulled the child into a hug and giggled at his adorableness.
"So what's strange about this murder?" John asked, crouching next to the body, "Lestrade wouldn't call you out for a stabbing."
"Yes," Sherlock said, "Right." He took out his magnifying glass and inspected the wound closer, furrowing the brow in the way he did when he was thinking hard about something. "He's in his late twenties, unemployed, travels a lot. He's dyed his hair recently, all his clothes are brand new..."
"Serlo.. Serlock?"
"Sherlock, Hamish!" Sherlock corrected, "What have you found?" Hamish had removed the victims shoes, and grinned wildly as he opened his hand to reveal a red jewel. The puzzle started to piece together in Sherlock's mind, "Hamish you are brilliant!" He picked the boy up in his arms and swung him around, causing him to giggle and squirm.
"Care to fill me in?" John asked. Sherlock turned to him.
"He's foreign, French I'd say. John, we've got ourselves another smuggler gang!" He tousled Hamish's hair, "I'm so proud of you!"