SYDNEY-Australian police offered a record $4.75 million in rewards Saturday to catch the serial killer or killers behind the murders of six Melbourne women in the 1980s.

The women, ranging in age from 14 to 73, disappeared in separate incidents as they traveled on foot around Melbourne over an 18-month period in 1980-1981.

Their remains were found in scrubland in several locations on the outskirts of the city.

The police in Victoria state, where Melbourne is located, announced on Saturday six rewards of AUS$1 million ($780,000) each for information leading to the arrest and conviction of whoever was behind the murders.

“Investigators are seeking public assistance to help solve these six murders, and are appealing directly to any persons with knowledge of these crimes and of those responsible to come forward and contact police,” the department said in a statement.

It said the AUS$6 million was the largest reward amount ever offered by the department.