A second man has been arrested in connection with the theft of an 18-carat gold toilet from Blenheim Palace.
The artwork, which is fully functioning and called America, was taken in the early hours of Saturday, Thames Valley Police said.
Officers are still looking for the stolen loo.
It was installed opposite the room in which Sir Winston Churchill was born at the 18th-century Oxfordshire estate.
Its removal caused significant flood damage because it had been plumbed in for visitors to use.
Made by Italian conceptual artist Maurizio Cattelan, it is worth about £4.8m, Blenheim Palace chief executive Dominic Hare said.
Police said a 36-year-old man from Cheltenham had been arrested on suspicion of conspiracy to burgle, and released under investigation.
Another man, 66, was arrested on suspicion of burglary and released on police bail until 9 October.
The artist praised the thieves as “great performers” and appeared to make light of the situation.
“When this morning I was informed about the robbery I thought it was a prank and it took me a while, after a few checks, to come to the conclusion that it was true and it wasn’t a surreal movie where instead of the jewels of the crown, the thieves went away with a b***** toilet,” Mr Cattelan said in a statement.
“I always liked heist movies and finally I’m in one of them.”
The artist joked: “Dear thieves, please, if you are reading this, let me know how much you like the piece and how it feels to pee on gold.”
The toilet was installed at the palace as part of Mr Cattelan’s first solo exhibition for 20 years.