For Detective Inspector Mark Steel, the fact that several people came forward in December with additional information, following a police re-examination of the Fairbairn pine forest location where Ms Rowland's body was found, confirmed his long-held suspicions.

"I have no doubt that even after all these years, someone in Canberra either knows what happened that night or has some key information which would further this investigation significantly," Inspector Steel said.

"In my experience that's not unusual with cases such as this: there is almost always someone out there who holds that vital piece of information or evidence we are looking for."

One man who contacted police late last year said he had never seen the previous appeals for information; that new account he provided "added to our list of inquiries", investigators said cautiously.

More stimulus will be added on Friday as police return to the section of Parkes Way where Ms Rowland's Morris 850 was found locked, abandoned and out of fuel. It is believed that when her vehicle ran out of fuel, she began hitchiking and was then picked up by the person who abducted and murdered her.

February 26 marks the 50th anniversary of Keren Rowland's disappearance.

She was just 20 years old when she was abducted on the evening of the opening day of the Royal Canberra Show.

Her remains were found in the Fairbairn pine forest to the south-west of Canberra Airport on May 13 of the same year.

Her killer has never been identified.

More than 30 people, all men, have been interviewed by police, and there's little doubt that the investigative effort, both at the time and in the years which have followed, has been an intensive one.

Crime Stoppers websites and information tip-off lines didn't exist 50 years ago, nor did modern forensics techniques.

Much of the work done by police at the time was done in the old-fashioned way: combing through known offenders, carefully interviewing them, and chasing down every possible lead, no matter how unlikely.