The ACT government has announced rewards of up to $500,000 for information that leads to successful prosecutions in five long-running homicide or missing-person cases in Canberra.

The new rewards are designed to encourage people with information — including people who may have stayed silent for decades — to contact police.

The five cases involve Elizabeth Herfort, Keren Rowland, David Abuoi, Megan Louise Mulquiney and Troy Hugh Forsyth.

All remain unresolved. The announcement does not identify a new suspect or signal that police have made a fresh breakthrough.

Why rewards are being offered now

Cold cases can remain open for decades because investigators lack one critical piece of evidence: a witness, a confession, a reliable identification, a vehicle detail or information that connects an existing clue to a person.

Police can re-examine forensic material and old files as technology improves, but some cases still depend on people coming forward.

ACT Police, Fire and Emergency Services Minister Marisa Paterson said the government hopes the financial incentive will motivate someone with relevant information to speak.

ACT Chief Police Officer Scott Lee has similarly emphasised that one piece of information can be enough to help investigators progress a case.

The rewards are available for information that leads to the successful prosecution of those responsible for the relevant death or disappearance, subject to the conditions of each offer.

Elizabeth Herfort

Elizabeth Herfort was 18 when she disappeared in June 1980.

Police records and current reporting say she was last seen in central Canberra around the time she was studying at the Australian National University.

Her disappearance has remained unresolved for more than four decades.

In a case that old, investigators face obvious challenges: memories fade, potential witnesses die, businesses close and physical locations change.

But old cases can also benefit from new technology, digitised records and renewed public attention.

The reward does not indicate police have determined exactly what happened to Herfort. Her case remains a missing-person investigation with the possibility of criminal involvement being examined.

Keren Rowland

Keren Rowland was 20 when she disappeared in February 1971.

Her remains were found near the Air Disaster Memorial outside Canberra about three months later.

Despite the passage of more than 50 years, the case has not been solved.

Historical homicide investigations can be particularly difficult because forensic standards, evidence storage and investigative technology were very different when the crime occurred.

Modern investigators can sometimes re-examine old evidence with methods that did not exist at the time, but success depends on what material remains available and in what condition.

David Abuoi

David Abuoi, also known as Gabrielle Malak Arok, was 35 when he was last seen in Canberra’s central business district in July 2012.

Police suspect he was murdered, but his disappearance remains unresolved.

A case from 2012 sits in a different technological era from cases dating to the 1970s and 1980s. Investigators may have access to more digital, telecommunications or surveillance-related material, but that does not automatically produce an answer.

The reward is intended to reach people who may know what happened or who may be able to explain relationships and events surrounding the disappearance.

Megan Louise Mulquiney

Megan Louise Mulquiney was 17 when she disappeared in July 1984.

She was last seen outside Woden Plaza and did not return home.

Her family has lived with the uncertainty of her disappearance for more than four decades.

Missing-person cases can be especially difficult for families because there may be no confirmed account of what happened and no final location to focus an investigation.

The reward creates another opportunity for anyone who heard something at the time, saw suspicious behaviour or received later information to reconsider whether it could be important.

Troy Hugh Forsyth

Troy Forsyth was 17 when he was fatally struck by a panel van while walking home with friends along Kent Street in Deakin in the early hours of 1 March 1987.

Police conducted what has been described as an exhaustive investigation, but the vehicle and its driver were never located.

The case remains open.

A hit-and-run investigation can turn on details that appear minor to a witness: the colour or shape of a vehicle, damage seen afterwards, a change in someone’s behaviour, or a conversation in which a person described an incident.

After so many years, police are hoping that people who were reluctant to speak at the time may now feel differently.

Indemnity may be considered in some circumstances

The ACT government has said appropriate indemnity from prosecution may be considered for an accomplice to a homicide who is the first to provide information.

That does not mean immunity is automatically available to anyone involved in an offence.

Any such arrangement would be subject to legal assessment and the specific circumstances of the information provided.

The purpose is to create an additional incentive for someone with inside knowledge to help identify a person responsible for a serious crime.

Rewards do not reduce the standard of proof

A large reward can generate tips, but police still have to test those tips against evidence.

Investigators cannot treat a claim as reliable simply because a person is seeking reward money.

Information may need to be corroborated through records, forensic evidence, independent witnesses or details that only someone with genuine knowledge would know.

Any prosecution would still have to meet the normal criminal standard in court.

The accused would retain the presumption of innocence, and the prosecution would need to prove the charge beyond reasonable doubt.

Why cold cases can move after decades

Time makes investigations harder, but it can also change the social circumstances around witnesses.

A person who once feared someone may no longer be under that influence. Relationships can break down. Loyalties can change. A person who was young at the time may decide later in life that they want a family to have answers.

Advances in forensic science can also give old evidence new value, particularly when DNA or other biological material was preserved.

Digital databases make it easier to compare information across jurisdictions and identify patterns that investigators working decades ago could not access quickly.

None of those developments guarantee a result, but they explain why police continue reviewing unresolved homicide and disappearance cases.

Canberra has seen old cases solved before

ACT Policing maintains a homicide team that reviews cold cases and existing rewards.

One recent example of the value of persistence is the investigation into the death of Irma Palasics. Arrests were made decades after her killing, showing that an old case does not necessarily become impossible to solve.

Each investigation is different, and that example should not be read as evidence that the five newly rewarded cases are close to resolution.

It does demonstrate why police keep files open and return to old evidence when new information or technology becomes available.

What police want from the public

The government and police are asking people with information about any of the five cases to contact Crime Stoppers.

Useful information does not need to be a complete account of the crime.

A witness may remember a vehicle, a conversation, a person’s location, an object, or a change in behaviour. Investigators can assess whether that detail fits with evidence already held.

People should avoid conducting their own investigations or publicly naming people based on rumours. Posting an unverified accusation online can harm innocent people and complicate police work.

The correct approach is to give information directly to investigators so it can be assessed confidentially and lawfully.

The families remain at the centre of these cases

Behind each reward is a family that has lived for years without a complete answer.

For relatives of missing people, uncertainty can be especially prolonged because there may be no confirmed death, no known crime scene and no clear explanation of what happened.

For relatives of homicide or fatal hit-and-run victims, the absence of accountability can create a different form of unresolved loss.

The reward program cannot promise an outcome.

Its purpose is to reopen a pathway for information and give investigators another tool to pursue cases that have resisted previous efforts.

What is confirmed now

The ACT government is offering rewards of up to $500,000 linked to five unresolved cases. The money is intended for information that leads to successful prosecutions where criminal responsibility can be established.

No new offender has been identified publicly, and no one should be treated as responsible on the basis of the reward announcements alone.

The cases remain open, and the next step depends on whether new information emerges that investigators can verify.

For anyone who has carried relevant information for years, police are making the message clear: it may still matter, and it is not too late to come forward.