Australian killer escapes prison farm

One of Western Australia's longest-serving prisoners, locked up indefinitely for murdering a young couple while on the run from jail, has escaped from a minimum security prison farm.

It was Brian William Edwards' third escape from prison in a near 40-year criminal career. Police describing the 48-year-old as extremely dangerous, unpredictable and resourceful.

He walked out of the minimum-security Karnet Prison farm 73km from Perth on Monday night.