Arsonists torched a clubhouse during an attack at a golf course.
The building at Lofthouse Hill Golf Club was gutted by the blaze on Thursday night.
Detectives said a window was smashed and flammable liquid was poured into the clubhouse before it was set on fire sometime between 10pm and 11.30pm.
The function room, at the Leeds Road club, was badly damaged and other rooms have been heavily smoke damaged.
Detectives are appealing for anyone with any information or who saw anyone acting suspicious around the time of the blaze to contact DC Clive Newman at Leeds District CID on 101.
Alternatively call Crimestoppers, anonymously, on 0800 555111.