Private investigators can act as an alternative or a supplement to police.
Hiring a private investigator
Going missing is not a crime in Australia, so police cannot make every missing person a priority. Private investigators aren’t cheap, but some may be willing to offer their services pro bono. They may want you to advertise their company (through Facebook, Twitter, a logo on your website etc.) in return for their assistance.
Any important information uncovered by a private investigator should be shared with police.
Find a private investigator near you by searching Google.