He stood now near the constable, in his usual unobtrusive readiness.

He did not speak, but I saw a look of understanding in his eyes as he nodded his head to Colonel Sapt.

They were well matched, that pair, hard to move, hard to shake, not to be turned from the purpose in their minds and the matter that lay to their hands.
"Yes, he'd probably be taken or killed," said Sapt.
"Then let's do it!" I cried.
"With the queen's letter on him," said Colonel Sapt.
I had forgotten.
"We have the box, he has the letter still," said Sapt.
I could have laughed even at that moment.

He had left the box (whether from haste or heedlessness or malice, we could not tell), but the letter was on him.

Taken alive, he would use that powerful weapon to save his life or satisfy his anger; if it were found on his body, its evidence would speak loud and clear to all the world.