A quiet South Australian community is mourning the loss of a young mother and her toddler after a tragedy at Port MacDonnell, while police continue investigating the circumstances surrounding the disappearance of her infant son.

Helena Wright, 36, and her 23-month-old daughter were found dead after emergency services were called to Cape Northumberland near Port MacDonnell in South Australia’s south-east. Her three-month-old son remains missing despite an extensive land, sea and aerial search involving police, the State Emergency Service and specialist rescue crews.

Police have now confirmed they are treating the deaths as a suspected murder-suicide following an extensive investigation.

Investigators say there is currently no evidence suggesting anyone other than Ms Wright and her children were involved in the incident.

The matter has been referred to the South Australian Coroner, with detectives continuing to examine the family’s recent movements and interactions with authorities.

The tragedy unfolded after a passerby discovered Ms Wright’s white Isuzu MU-X parked near the cliff edge with its engine still running.

Emergency services were immediately deployed to search the rugged coastline.

Rescuers later recovered the bodies of Ms Wright and her young daughter from the ocean below the cliffs.

Despite an intensive search extending over several days, the infant boy has not been located.

On Wednesday, South Australia Police formally suspended the major search operation after receiving expert advice that the child could not have survived the time elapsed or the severe environmental conditions.

Authorities said shoreline patrols would continue, but the organised rescue effort had concluded.

Police described the decision as heartbreaking but necessary given the available evidence and the dangerous weather affecting the coastline.

Investigators have also revealed that Helena Wright attended the Mount Gambier Police Station the day before the tragedy.

The following morning, after concerns were raised by a friend, officers conducted a welfare check at her home.

When police arrived, no one was present.

Only later was her vehicle discovered abandoned near Cape Northumberland, prompting the large-scale emergency response.

Police have not publicly disclosed the reason for Ms Wright’s visit to the station and have indicated that this aspect of the investigation remains under examination.

Commissioner Grant Stevens said investigators are carefully reviewing all available information, including previous contact between the family and government agencies, to establish a complete understanding of the events leading up to the tragedy.

The deaths have sent shockwaves through the Mount Gambier region.

Friends and neighbours described Ms Wright as a devoted mother who was actively involved in the local community.

She volunteered with the Mount Gambier Toy Library, where colleagues remembered her as a kind, thoughtful and generous person who enjoyed supporting local families.

Community members have spoken of their disbelief that such a tragedy could occur, describing the loss as devastating for everyone who knew the family.

South Australian Premier Peter Malinauskas expressed his condolences to the family and to the wider community.

He described the incident as an unimaginable tragedy and urged the public to avoid speculation while the coronial investigation proceeds.

Police have similarly asked the community to allow investigators to establish the facts before drawing conclusions about the circumstances of the case.

Superintendent Trent Cox acknowledged the emotional toll the operation had taken on emergency personnel and volunteers who spent days searching difficult coastal terrain in dangerous weather conditions.

He thanked search crews, local residents and volunteers for their commitment throughout the operation despite increasingly poor prospects of finding the missing infant alive.

The investigation has also renewed discussion about mental health support available to families experiencing crisis.

Police have not publicly identified any medical diagnosis or specific circumstances that may have contributed to the incident.

Accordingly, authorities have cautioned against drawing conclusions until the coronial process has been completed.

Experts note that coronial investigations examine all available evidence—including witness statements, medical information and forensic findings—before determining the circumstances surrounding unexpected deaths.

Those investigations can take many months before final findings are released.

As part of the inquiry, detectives have interviewed family members, including the children’s father, and continue reviewing physical evidence collected from the scene.

Authorities have again confirmed there is no indication of any ongoing risk to the wider community.

The tragedy has resonated across Australia because of both the ages of the children involved and the extraordinary efforts undertaken to locate the missing baby.

Images of rescue crews searching rugged cliffs and rough seas became a powerful reminder of the emotional burden carried by emergency responders during incidents involving young children.

Community support services, including psychologists and welfare workers, have since been made available to emergency personnel, volunteers and others directly affected by the tragedy.

For residents of South Australia’s south-east, the loss of Helena Wright and her young daughter has left a profound sense of grief that extends well beyond those who knew the family personally.

As investigators continue their work, police have urged anyone with information about the family’s movements before the incident to contact Crime Stoppers or South Australia Police.

Although the organised search for the missing infant has ended, authorities say the investigation into the tragedy itself remains active.

The case now enters the coronial process, which is expected to examine every aspect of the circumstances leading to one of the state’s most heartbreaking family tragedies in recent years.