Arsonists torched a caravan, motorbike and a car in a series of fires in Sheffield, Rotherham and Doncaster.
Firefighters were called to Canklow Road, Canklow, at around 8.15pm on Thursday after a caravan was set alight.
Crews from Rotherham and Parkway spent around half-an-hour.
A motorbike was also deliberately set alight on Castlebeck Avenue, Castlebeck, Sheffield, at around 12.45am on Friday.
A BMW was also torched on Dorado Drive, Balby, Doncaster, at around 2am.
Anyone with any information about any of the incidents should call police on 101.