ACT Policing has renewed the call for information regarding the murder of Canberra childcare worker Kathryn Grosvenor more than a decade ago.
The body of the 23-year-old Nicholls woman was found by a canoeist in Lake Burley Griffin on March 9, 2002.
A $500,000 reward for information leading to the apprehension and subsequent conviction of the person or people responsible for the murder was posted in September last year, which Detective Senior Constable Sarah Casey hoped would appeal to potential witnesses.
''In March last year, a witness came forward with information regarding two men loading concrete on Anthony Rolfe Drive into a black ute,'' she said.
''I would like to appeal to those two men or the people who know them to seriously consider this reward and contact Crime Stoppers.
''This amount of money could be life-changing.''
Ms Grosvenor's mother, Kerrie, has previously spoken out about the importance of witness contributions.
''Anything, no matter how insignificant people might think it is, it could be a matter of getting that final result,'' she said.
Kathryn Grosvenor was last seen at her Nicholls home on Sunday, March 3.
There were two sightings of Grosvenor in the Gold Creek area the night she went missing, both unconfirmed.
One was a sighting at the George Harcourt Inn in Nicholls, where she is thought to have bought cigarettes between 9.05pm and 9.15pm.
Described as 178 centimetres tall with a slim build and long brown/red hair, Grosvenor was last seen wearing dark coloured hipster pants and electric blue platform shoes.
ACT Policing said an indemnity from prosecution would be considered for any accomplice who first gives information.