Australian surfers killed in Mexico were shot 'trying to stop theft of pickup truck'

Authorities have confirmed that three tourists found dead in Mexico were shot in the head and their bodies were dumped in a well.

Australian brothers Jake and Callum Robinson, aged 30 and 33, vanished along with their 30-year-old American friend Jack Carter Rhoad on April 27 during a surfing trip in Ensenada.

The three men were on a camping and surfing trip, posting idyllic photos on social media of waves and isolated beaches, before they went missing.

After travelling to Mexico to help identify them, relatives confirmed their identities on Sunday, a state prosecutor said.

State Attorney General Elena Andrade told the parents and diplomatic officials that there was "total institutional commitment to continue with the investigation of these unfortunate events until those responsible receive the full weight of the law".

The men were likely killed while trying to prevent the theft of their pickup truck, with the attackers targeting the vehicle for its tyres, Ms Andrade added.

The victims resisted and were shot.

Authorities discovered their bodies in a four-metre-deep well approximately six kilometres from the attack site in Santo Tomás on Friday.

Nearby they found abandoned tents, a burnt white pickup truck and a phone linked to the surfers. Another older, unrelated body was also found in the well.

Deborah and Martin Robinson, the parents of the brothers, said on Friday that Callum had been living in the US pursuing his dream of becoming a professional lacrosse player.

Jake was visiting him on "the trip of a lifetime" before starting a new job as a doctor in Victoria.

“Callum and Jake are beautiful human beings. We love them so much and this breaks our heart,” they said.

Three suspects are being held in connection with the case.

The thieves allegedly covered the well with boards.

"It was literally almost impossible to find it," Andrade Ramirez said, and it took two hours to winch the bodies out of the well.

Australian Treasurer Jim Chalmers expressed sympathy for the Robinson family.

"I think the whole country's heart goes out to all of their loved ones. It has been an absolutely horrendous, absolutely horrific ordeal and our thoughts are with all of them today," he said at a news conference Monday in the capital, Canberra.

Dozens of mourners, surfers and demonstrators gathered in a main plaza in Ensenada, the nearest city, to voice their anger and sadness at the deaths.

"Ensenada is a mass grave," read one placard carried by protesters. "Australia, we are with you," one man scrawled on one of the half-dozen surf boards at the demonstration.

A woman held up a sign that read "They only wanted to surf — we demand safe beaches."

Surfers later performed a "paddle-out" ceremony where they formed a circle on their boards in the ocean.