Six boys have now been arrested in connection with a spate of arsons in the Maltby area.
The boys, who are all aged between 15 and 17-years-old, have been bailed pending further enquiries.
The three fires were started in the early hours of Friday, December 5. The first incident occurred at 2.19am at a garage in Blyth Road when a number of vehicles were set alight.
Just half an hour later, another fire was set at 2.49am in Millicent Gardens.
A camper van and a Vauxhall Astra van were destroyed by the fire which also spread to nearby properties.
The occupants of three properties were evacuated. Significant damage was caused to the front of the properties.
The third incident was reported at 4.32am when a caravan parked on a driveway in Mortimer Road was damaged. The fire service attended and put out the fire.
No one was injured during the incidents.
Call police on 101.