Two children and their father all had gunshot wounds before their car was driven off the wharf at Port Lincoln in SA, police have said.

Autopsies on Damien Little and his sons revealed they had all been shot before the white station wagon was driven off Brennan's Wharf at high speed early on Monday.

The car plunged into up to 30 metres of water in what police have said was a suspected murder-suicide.

The development came as Little's grieving wife and mother of Hunter and Koda, Melissa Little, released a statement.

She said her husband put his family first and loved his two children very much.

Tributes have been growing in Port Lincoln as the community grieves. ( ABC News: Candice Marcus )

"Damien was my childhood sweetheart who became my loving husband," she said.

"Damien valued and appreciated our close-knit family ... we were his whole world. He spent every hour providing quality time and teaching the boys how to live and grow.

"Damien I loved you so much you have left a huge hole in my heart, our memories I will cherish forever. You will not be forgotten.

"My wish is for Damien to be remembered as a well-respected and valued member of our family and our community.

"My two precious boys have left this world way too soon and my heart is broken.

"I will miss them and think about them each and every day. Their futures were full of endless possibilities.

"Koda had the biggest heart, so loving and caring. He always loved a hug, had so much enthusiasm and was a willing helper.

"Hunter was such a happy, content and smiling baby. His laughter was infectious and his cheeky little personality was just beginning to emerge."

People left tributes earlier this week at the wharf their respects to the family. ( ABC News: Candice Marcus )

A second statement from extended family members, including Ms Little, Dale and Debby Goldsworthy and Ken and Sue Little, thanked emergency services, Port Lincoln residents, the city's Mayor Bruce Green, South Lincoln football club and the Port Lincoln Ports Corporation for their support.

"We are never prepared to face such unexpected tragic events," it read.

"The outpouring of love, support, well wishes and offers of help from family, friends and community, is such a comfort at this sad time."

Community continues to come to grips with loss

A coronial investigation is ongoing and issues including domestic violence and mental health will form part of the report for the coroner.

A rifle was recovered from the vehicle.

The deaths have shocked the local community, where Little was a popular member of a local football team, with Mayor Bruce Green describing it as "one of the saddest days in our history".

A growing memorial of floral tributes and other items such as teddy bears on the wharf has since been moved to a nearby location.

A trust account set up to receive donations for Ms Little to help cover the funeral costs has now received more than $25,000, according to a Facebook post made on a page created by the fund's organisers called 'A Little Help'.

"We are overwhelmed by the support shown for Mel. The current donation balance is at $25,301," the post said.

The Lincoln South Football Club is holding a special meeting on Saturday afternoon where members and other residents will come together to support each other and reflect on the tragedy.

They will light candles and say a prayer for the family.