A bank theft has been committed and, after due investigation, the police has detained four suspects.
During the course of verbal questioning, the four suspects recorded the following statements.

• Al: The thief was Bud.
• Bud: The thief was Dax.
• Cal: I am innocent.
• Dax: When Bud said that it was me, he lied.

Determine the perpetrator, whenever:
(I) Precisely one of the suspects is lying, and the others are speaking the truth.
(II) Precisely one of the suspects is telling the truth, and the others are speaking falsely.