Three tourists found dead in Mexico were shot in the head and their bodies dumped in a well, authorities have confirmed.
Officials believe the men were attacked trying to stop the theft of their pickup truck.
Australian brothers Jake and Callum Robinson, 30 and 33, and their American friend Jack Carter Rhoad, 30, disappeared on 27 April while on a surfing trip in Ensenada.
Relatives of the three men identified their bodies on Sunday after travelling to Mexico to assist authorities, a state prosecutor said.
The attackers wanted the vehicle for its tyres and shot the tourists when they resisted, Baja California state prosecutor Maria Andrade suggested.
Their bodies were found in a 4m (15ft) deep well about 6km (4 miles) from the site of the attack in the town of Santo Tomás on Friday.
Abandoned tents, a burnt white pickup truck and a phone linked to the missing surfers were found nearby.
A fourth body was found in the well, but had been there longer and was unconnected to the case, officials said.
Two men and a woman have been detained on suspicion of direct or indirect involvement in the attack. One man with a previous criminal record has been charged with "forced disappearance".
Earlier, the FBI said it was looking into the case and was in touch with international partners.
Baja California is one of Mexico’s most violent states, as local drug gangs fight turf wars.
In 2023, it had the country's second highest murder rate, after the state of Guanajuato, according to official figures.
National Defence Secretary Luis Cresencio Sandoval said earlier this year that 85-90% of murders committed in Baja California were linked to drug trafficking and organised crime.
But the Ensenada area, about 120km (75 miles) south of the US-Mexico border and known for its surfing conditions, is considered safer and has long attracted tourists from California.
The brothers' parents - Deborah and Martin Robinson - said Callum had been living in the US, chasing his dream of becoming a professional lacrosse player.
Jake was on "the trip of lifetime" to visit him before starting a new job in Victoria as a doctor, they said on Friday.
“Callum and Jake are beautiful human beings. We love them so much and this breaks our heart.”
Friends of the brothers have also flooded social media with tributes.
Callum's teammates at Stevenson University Lacrosse club said the athlete was a larger-than-life personality.
"With his beautiful long hair and charming smile, he truly embodied the nickname ‘big koala’ - warm, friendly, and always there to lend a helping hand," a statement from the club said.
His girlfriend, Emily Horwath, said her heart was "shattered into a million pieces".
"I don’t have the words right now... I will love you forever," she wrote in a post on Instagram, alongside pictures of the couple.
Carter Rhoad's social media accounts showed happy snaps of him proposing to his partner less than a year ago.
A fundraiser set up by friends of his family said he and the Robinson brothers had "brought immeasurable joy, love, and kindness" to the world.
Australian Treasurer Jim Chalmers said the country was thinking of the Robinson family.
"It has been an absolutely horrendous, absolutely horrific ordeal and our thoughts are with all of them today,” he said at a news conference on Monday.
The killings have sparked fear and anger in the Ensenada region.
Scores of protesters marched through the city on Sunday, carrying surfboards plastered with slogans written in Spanish.
“They only wanted to surf - we demand safe beaches," one said. "Australia we are with you," another said.
A group of surfers later performed a “paddle-out” ceremony, an ocean vigil to honour the trio.
It is not the first time that Australian surfers have been killed while holidaying in Mexico.
In 2016, Dean Lucas and Adam Coleman were murdered in north-western Sinaloa state when they fought back during an attempted robbery.
Their bodies were found in their burnt-out camper van weeks later.
On X, the platform formerly known as Twitter, Mexico’s foreign ministry said that Mexico’s ambassador to Australia had traveled to Baja California to work with Australian consular officials and help the families of the victims.
State Department figures show that at least 1.6 million US citizens live in Mexico, which is also the top destination for US tourists globally, with more than 30 million visitors in 2022.
In 2022 - the last year for which State Department data is fully available - 192 Americans died in Mexico, of which 46 were ruled as homicides.
