“I’m not sure that I can accept all your theories.”
Pescatelli smiled, as though he’d lured Augustinto a trap.
“That’s why I need Kirk to shoot the ghosts,” he said, “I need to shore up the points in the book. I gave him a list of every ghost I knew of in town.”
Idiot, August thought, Pescatelli was an idiot. But he nodded, content to let Pescatelli think he won a valuable hill in their war of wills.
“As you say,” he said, latching his case.
What's the meaning of this "latching his case". I don't think that's an idiom because I can't find it anywhere on the Internet.