Greg Lestrade tried answering the question for the rest of his life.
Did Sherlock know exactly what was going to happen ?
What was said by the two enemies during the hours before dawn?
What was inside the teddy bear ?
It was a like a treasure hunt, indeed.
Under the earring chair was stuck the picture of a crime scene surrounded by yellow barrier tape. At the river banks where they had found Rachel Doyle was a plastic box with a post-it inside, on which was written an address. At this address, they found GPS coordinates. At the location, a map with a street name underlined.
In the street, Holmes' car.
John found it just a few minutes before the squad reached the last clue, tracing the sender of the messages found in the detective's cell phone.
Suddenly, for some unknown reason, "F"'s mobile had been switched on.
By the time they drove like crazy to the location, the night had ended and dawn began to break in the night sky, piercing the purple clouds with a golden arrow.
John Watson, the inspector Lee and Greg Lestrade arrived first and didn't wait. They climbed the stairs four at a time, hands clutched on their weapons, panting.
They were on the sixth floor when they heard the gun shot.