Tasmania Police is now offering $500,000 for information that could help solve a number of mysterious murder cases.
There are currently seven unsolved murder or suspected murder investigations in the state, with rewards on offer for information leading to a conviction.
Those amounts ranged from $30,000 to $250,000, but will now each attract the $500,000 reward.
Assistant Commissioner Jonathan Higgins says the boosted rewards are significant.
“These rewards are an important investigative tool that may entice people with crucial information to come forward and provide this to police,” Assistant Commissioner Higgins said.
“In the passage of time someone’s circumstances and allegiances may have changed and the offer of a life-changing amount of money may be the motivation they need to come forward."
Police are seeking information on the disappearance of young Burnie mother Helen Munnings, who vanished on the 23rd of July 2008.
They're also seeking help in relation to Christopher Dean Watkins, who was last seen at a unit in the Launceston suburb of Mayfield in August 2013.
Other unsolved investigations include the disappearance of southern teenager Eve Askew in 1991, the case of Paul Winston Byrne, who was reporting missing in 1996, and the notorious disappearance of Nancy Grunwald, who vanished from the east coast in 1993.
Police are also hoping for tip-offs over the murders of Simon Crisp in 2013, and Victoria Cafasso, who was killed on Beaumaris Beach on the east coast in 1995.
Assistant Commissioner Higgins wants to see all seven unsolved murder cases closed.
“Families always deserve answers to what happened to their loved ones and we owe it to them to find those answers,” he said.
Anyone with information that could help solve these cases is asked to contact Police on 131 444 or Crime Stoppers on 1800 333 000 or online at crimestopperstas.com.au.