UPDATED 11AM
Police say the man is believed to be travelling on foot around Mission Road, in the Kellerberrin and Bencubbin areas.
He is believed to be armed and dressed in camouflage clothing.
Residents in the area are urged to stay inside and avoid travelling by any means.
***
People living in Kellerberrin have been advised to stay indoors after a police incident in the town this morning.
It has been alleged a man discharged a firearm at the Moylan Grain Silos in the town at 8.40am, before leaving the area.
It is understood the vehicle was a 2007 grey Holden Commodore, registration 1CRB 764.
Anyone who sees the vehicle should call police immediately on 000.
Just after 10.30am, police have extended the public warning, saying residents in the Bencubbin area should also stay indoors and stay away from Mission Road, which connects with the Bencubbin-Kellerberrin Road.
One person has been injured and was conveyed to hospital via ambulance.
"Members of the public in the area are advised to remain indoors at all times," advised WA Police Force on social media.
"Anyone with information is urged to contact police immediately on 000.
"More information will be provided when it becomes available."
It is understood there is a heavy police presence in the town at the moment.
Keep a look out
Anyone who knows the whereabouts of Lachlan Bowles (pictured above in photo by WA Police) should report it to police immediately.
He is described as approximately 175 centimetres tall, slim build, brown hair and blue eyes.
