And those shocked by the deaths have been urged not to rush to blame the father as community leaders seek to prevent the tragedy being repeated.
The bodies of Damien Little and his sons Hunter, aged less than one, and four-year-old Koda were pulled from the water off a Port Lincoln wharf in South Australia on Monday.
Police said Little deliberately drove off the wharf into water up to 30 metres deep.
A family acquaintance and local businessman said he was still numb from the news.
“It’s just a shocking thing to have happen out of the blue and for no reason that we knew of,” Wheatsheaf Hotel owner Peter Watherston said.
“He and his brother used to pop out for a beer. He was just a normal, everyday Australian bloke.”
Little and his wife Melissa operated a floor-covering business and he had also played for the Lincoln South Football Club.
Club president Brenton Dennis said Mr Little was respected and well liked.
“I think everyone is pretty gutted and distraught and bewildered by what’s happened,” Dennis told ABC radio.
Little’s family told the Adelaide Advertiser the 34-year-old had suffered mental health issues for the past three years.
“We had noticed a change,” his mother Sue was quoted as saying.
“We tried to help him, we all did. But you can’t help somebody who can’t help himself.
South Australian Commissioner for Victims’ Rights Michael O’Connell said the heart-wrenching incident had caused anguish for the family and friends.
“But also to many who find murder by a parent to be among the cruellest of tragedies,” he said.
“As people seek to come to terms with what has happened, they should be careful not to victim-blame.
“We do not know the reasons Damien did what he appears to have done and speculating helps neither the family nor the people of Port Lincoln.”
Port Lincoln Mayor Bruce Green said the past 24 hours had been the worst day of his working life.
“This has taken everyone by surprise. It’s a dreadful thing,” he said.
“People are really trying to understand how this tragic event could have occurred.
“Apart from supporting family and friends, the next thing we need is how do we deliver support in the community to ensure these things don’t happen in the future.”
As well as tributes on social media, locals have created a makeshift memorial of flowers and teddy bears along the edge of the wharf as police released two photos which appeared to show a happy family.
In one, Mr Little and his wife are shown sitting on a beach with their two smiling young boys resting in their laps.
Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14 or MensLine Australia 1300 78 99 78
Help our journalists uncover the facts
In times like these InDaily provides valuable, local independent journalism in South Australia. As a news organisation it offers an alternative to The Advertiser, a different voice and a closer look at what is happening in our city and state for free. Any contribution to help fund our work is appreciated. Please click below to donate to InDaily.