The historic bridge at the site was damaged sometime overnight and before 8am on Saturday, March 3, then on Monday, March 12, at around 12.30am, the Bunk House was set alight while around eight people were sleeping inside.
A 27-year-old man was arrested on suspicion of criminal damage, theft of a vehicle and arson with intent to endanger life on March 15, but has since been released without charge.
Police Constable, Mark Dickson, said: “We are actively working to find out who’s behind these incidents.
“We are currently working on the notion that they are linked but at the same time, we are keeping an open mind.
“We believe that at least two offenders were involved in the arson who arrived and left on motorbikes. When the bridge was damaged, there were two cars involved, one of which had been stolen from Shirebrook in the days leading up to the incident and was found burnt out.”
“We need people to come forward with information, if they saw or heard anything out of the ordinary, please get in touch with us.”
Extra patrols are being conducted in the area and there is an officer presence at key times.
If you do have any information, please call the police on 101 quoting incident 156 of March 3 or incident 18 of March 12. You can also call Crimestoppers anonymously on 0800 555 111.