The perpetrator stole Hunwick's white VW Golf, as well as a club rucksack holding a laptop and GPS equipment used for training sessions to monitor the players' fitness.
"The laptop is useless to anyone apart from us as it just has data and spreadsheets on it, it is no good for going on the internet or anything like that and we just need to get it back to retrieve the data," Hunwicks told the club's official website.
"There were a number of things in the boot of the car that I was getting signed by the players to raise money for charity that I hope if anyone is offered them they will do the decent thing and contact the police.
"One of them was a shirt from the Challenge Cup Final last season which was distinctively embroidered with the details of the game, only a handful of these were produced for the backroom staff so if you are offered one please call the police and hopefully we can get it back and still raise much needed money for charity."
The staff member's bank cards were also stolen and later used in Bradford.