Sherlock strode into the office room, located a tray of evidence pieces, and picked up two small bags containing pills of identical appearance. "Mind if I borrow these?"
Lestrade looked up with a familiar exasperated expression. "Yes, actually, I mind quite terribly. You can't just waltz off with crime scene evidence whenever you please."
"I wouldn't need them if your so-called investigators would hurry up and do their job analyzing them," Sherlock said, a sneer creeping onto his face. He tossed the bags back onto the desk.
Lestrade eyed him suspiciously. "What do you need them for? The case is solved."
"Research," Sherlock replied shortly.
"Look," Lestrade sighed, "I might be able to get you a report of the analysis results once they come out. And I could possibly let you examine them yourself once all the loose ends are wrapped up on this case. But either way it'll take a while and it's not a guarantee."
Without another word, Sherlock turned on his heel and left the office.
No less than two hours later, Sherlock sat in his lab, carefully opening the first evidence bag. According to its label, this pill had been found next to the dead cabby. He twisted the capsule open and tapped out some of the contents into a test tube.
He was quite confident the poison the cabby had been using was strychnine. Death by asphyxiation and/or convulsions; fast-acting effects, but slow enough that Jennifer had had time to carve letters on the floor... yes, as unorthodox a choice as it was, it had to be strychnine.
Sherlock performed the chemical tests with the utmost precision, as always, but... this couldn't be. Negative results? He found a clean test tube and shook more of the pill's contents into it, redoing the tests even more carefully. Still negative.
Mentally reprimanding his racing heart, Sherlock picked up the second bag, the pill he had chosen, and prepared to run the test once more. Of course his pill wasn't poisoned - neither was poisoned, he was bluffing, just playing games!
But the test indicated otherwise.
Sherlock's fists clenched of their own accord. He stood up briskly and exited the lab, leaving the pills for someone else to take care of.