Who Stole the Tarts? Part V

Then who did steal the pepper? "My, my, this is really a difficult case!" said the King.

The next suspects, curiously enough, were the Gryphon, the Mock Turtle, and the Lobster. At the trial, the Gryphon said that the Mock Turtle was innocent and the Mock Turtle said that the Lobster was guilty.

Again, no innocent one lied and no guilty one told the truth.

Who stole the pepper?

(Source: Alice in Puzzle Land: A Carrollian Tale for Children Under Eighty by Raymond Smullyan)

As in the prior case, one individual is claiming the other is innocent and this instance is formally identical to that other one. This means that Gryphon and Mock Turtle are both innocent and truthful. Accordingly, the Lobster is guilty.