This site is an initiative from the Carnamah Historical Society & Museum. It was set up so that the public can volunteer from home and help to transcribe and/or index historical records. Examples of records include the WA Biographical Index and the Commonwealth electoral rolls for the Carnamah area - Irwin and Moore.
http://www.virtualvolunteering.com.au/volunteer
Lots of information on W.A. police from early years of the colony. go to 'Museums and Stories' then click on 'Historical snippets' to access a list of known early police officers. If your man is listed it is worth contacting the Society as they have a wonderful collection of material.
http://www.policewahistory.org.au/HTML_Pages/Museum.html
The Western Australian Police Gazettes 1876 to 1900 have been digitised and are available on the State Library of Western Australia website. Use them to research police or convict ancestors.
http://www.slwa.wa.gov.au/find/western_australian/police_gazettes