NSW Senior Deputy Police Commissioner Ken Moroney yesterday confirmed that homemade bombs had been found. One of the devices is suspected of starting a fierce bushfire that raged near houses at West Pennant Hills, northwest of Sydney yesterday. A second device was found intact in the Galston area, also in the city's northwest, but it did not spark a fire there. Mr Moroney would not describe the devices in detail because of fears of copycat firebugs. as arsonists use home-made bombs to keep NSW under siege. Two devices have been found in devastated areas. One of them might have lit a fire that threatened hundreds of homes in Sydney's suburbs. Police fear there may be a number of serial arsonists at work and are hunting a motorcyclist suspected of setting fires in the Blue Mountains.