Originally from Perth, Callum, 33, and Jake Robinson, 30, were on a surfing trip with American friend Carter Rhoad, 30, in northern Mexico when they failed to check in to a pre-arranged accommodation near the city of Ensenada.
When police arrived at their last known whereabouts, they discovered a campsite covered in blood.
Days later, three bodies were found in a well and on Sunday, their families confirmed their identities.
Prime Minister Anthony Albanese offered his condolences to the brothers' loved ones.
"This is a terribly tragedy and my heart goes out to them," he told reporters in northern Queensland on Tuesday.
"I've indicated that I wish to speak to them at an appropriate time of their choosing.
"To all of the family and the friends of these young Australians, the whole of Australia's thoughts are with you at this difficult time."
Baja California is well known for beautiful beaches and tiny villages and the trio's last images on social media showed them enjoying these sites.
But these northern border states are also rife with violent crime, with the Australian government's Smartraveller website warning of drug-related crime and gang violence.
Baja California state prosecutors believe the alleged killers were driving by when they spotted the foreigners' pick-up truck.
They attempted to steal its tyres and parts but the men resisted.
All three were found with bullet wounds to the head.
The alleged murderers attempted to destroy the evidence, burning the tent and driving the coveted pick-up away before setting it alight as well.
The bodies were dumped in a 4-metre deep well about 6km away, on top of a fourth body prosecutors say had been there much longer.
Three suspects are being held in connection with the case - two were caught with methamphetamine and one had one of the victims' phones.
A criminal charge of forced disappearance, equivalent to kidnapping, was laid against one of the three on Saturday.
The man, Jesús Gerardo, has a criminal record of drug dealing, vehicle theft and domestic violence.
Mexico's Foreign Minister Alicia Barcena has offered condolences to the men's family as surfers in San Miguel held a paddle-out in tribute to the trio.
More than 100 people also gathered for a vigil in San Diego, where Callum lived.
However, locals have noted the deaths of the three tourist were solved far quicker than the disappearances of thousands of Mexicans, many of whom were likely victims of the nation's drug wars.
In 2016, Adam Coleman and Dean Lucas - two surfers from Perth - were killed while travelling through Sinaloa.
with AP
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