St Marys police have established a task force to investigate a series of suspicious house and car fires in the region.
Strike Force Polygon will investigate nine incidents in suburbs including Colyton, Glendenning, Doonside and Schofields between August 2014 and November 2016.
Police say the fires may have been linked and targeted, and the victims were known to each other.
Five separate fires were allegedly deliberately lit on Desborough Avenue, Colyton between February 23 and November 26.
The fires in question included:
A Holden Statesman parked in a driveway on St Albans Road, Schofields was destroyed by fire about 1pm on August 6, 2014.
A Nissan Pulsar parked in a driveway at Woodley Crescent, Glendenning was destroyed by fire about midnight on October 19, 2015.
A single story house in Woodley Crescent, Glendenning was significantly damaged by fire about 11.40pm on October 21, 2015.
An Isuzu table top truck parked outside a house in Desborough Road, Colyton was damaged by fire at 1am on February 18, 2016.
The same Isuzu table top truck, a Holden Commodore and a Mazda 3 parked in the driveway of a house in Desborough Road, Colyton were damaged by fire just after 1am on February 23, 2016.
A Subaru Forester parked in the driveway of a house in Wilkie Crescent, Doonside was damaged by fire at 7am on June 24, 2016.
A Molotov cocktails was thrown into the front yard of a house in Desborough Road, Colyton about 2.30am on October 17, 2016, causing minor damage to the home
On October 18, at about 3am, a Molotov cocktail was thrown onto the roof of a house on Desborough Road, Colyton causing minor damage.
The front balcony of a house in Desborough Road Colyton was damaged by fire about 3am on November 26, 2016.
Anyone with information should contact Crime Stoppers, 1800 333 000.