A man has been arrested in connection with two incidents at Clumber Park.
Police were called to the site on Saturday, March 3, following reports of damage to a historic bridge.
The police then attended on Monday, March 12, at around 12.30am after The Bunk House was set alight.
The 27-year-old has been arrested on suspicion of criminal damage, theft of a vehicle and arson with intent to endanger life. He has been released on police bail.
Detectives continue to investigate the incidents and urge anyone with information to come forward.
Call the police on 101 quoting incident 156 of March 3 or incident 18 of March 12. Alternatively call Crimestoppers anonymously on 0800 555 111.