" Say it turns out to be the gun, and it’s going to be major-league coincidence if it doesn’t, you’re going to want to know whose gun it is, and if I tell you that I’ll have to tell you how I know it’s his and if I tell you that I’ll have to tell you things I don’t want to tell you.”
“But now that we know you’ve got it,” Lundquist said, “we can sort of insist.”
“True,” I said.
“And you know how hard we can insist when we feel like insisting. "

― Robert B. Parker , Pale Kings And Princes (Spenser, #14)