There is a monkey lover called Richard, and he collects stamps of monkeys in a binder. The last time he checked, he had 8351 stamps of monkeys.

One day, he found another 100 stamps. Going to his binder, he found that his stamps were all gone! He suspects these people:

Jeff: The landlord. Loves collecting stamps.

Jack: His brother. Loves stuffed animals, especially monkeys.

Thief: His other brother. A kleptomaniac.

Richard gathered them before him, and asked, "Where are my monkey stamps?"

And here are their alibis:

Jeff: I would love to have your stamps, unfortunately I don't have them.

Jack: Why would I want your silly 8351 stamps?

Thief: What stamps?

Richard said, "I know which one of you it is, and you had better give them back!"