The Thai police on Wednesday arrested a red-shirt activist for distributing the fake statement which said King Bhumibol had decided to appoint a Regent to act on his behalf.    The statement, falsely claimed to be from the Bureau of the Royal Household, was distributed on Monday night.    Krit B., the suspect, was accused of offences under Article 112 of the Criminal Code and offences under Computer Crime Act (CCA) for distributing false information on a computer system.    Krit is an active mem