Callum and Jake Robinson: Shock theory emerges about the Aussie brothers killed on a surfing trip in Mexico

A shocking new theory about the execution-style deaths of two Australian brothers and their American friend has raised fears over the possible involvement of drug cartels.

Callum and Jake Robinson and their American mate Jack Carter Rhoad were last seen on April 27 in the Mexican province of Baja California.

Mexican authorities said bandits attacked the three to steal the tires off their truck before killing them all and dumping their bodies in a disused well.

But the style of the slayings - a single gunshot to the head - has sparked fears locally about the possible involvement of drug cartels, which are rife in the region. 

The shock new details emerged as Callum and Jake's grieving parents performed the grim task of identifying their bodies on Sunday local time.

Callum and Jake Robinson (pictured) and their American mate Jack Carter Rhoad were last seen on April 27 in the Mexican province of Baja California 

Prosecutors released grisly details of the slayings including that of 30-year-old American Jack Carter Rhoad (pictured)

The Baja California Forensic Medical Service released the autopsy results as heartbreaking footage emerged of the Aussies' parents leaving Ensenada Forensics Lab  after identifying Callum's and Jake's bodies. 

Three Mexicans have already been arrested over the deaths but authorities are not ruling out further accomplices with possible links to organised crime. 

'We cannot rule out the possibility that there are additional individuals who were involved in this incident,' local Attorney-General María Andrade Ramírez said.

She added that the victims 'all have a hole in their head made by a firearm projectile'.

Hundreds of people marched through the nearby town of Ensenada on Sunday afternoon, demanding greater security measures amid a welter of cartel-fuelled violence. 

Callum and Jake's grieving parents performed the grim task of identifying their bodies on Monday (pictured: the boys' parents leaving the Ensenada Forensics Lab)

Some held surfboards emblazoned with messages written in Spanish, including 'Australia, we are with you' and 'They only wanted to surf, and they executed them', according to the ABC. 

Baja California is one of Mexico's most violent states, with the US State Department advising Americans to reconsider travel there due to crime and kidnapping. 

Tijuana, 100km north of where the three surfers were found and close to the US border, is plagued by violence and has the most homicides of any city in Mexico.

With a population of more than two million, it regularly has around 2,000 murders a year.    

By comparison, Houston, Texas, which has a similar population, saw 435 killings in 2022, according to Associated Press. 

Hundreds of people marched through the nearby town of Ensenada on Sunday afternoon, demanding greater security measures amid a welter of cartel-fuelled violence (pictured)

Jake Robinson (left) is pictured with his brother Callum (right) and their parents - who made the mercy dash from Perth to Mexico to identify their bodies

In December last year, furious drug lords hunted down corrupt officers who allegedly stole a drug shipment. 

The revenge hits led to the deaths of at least five officers.

It is believed the region is riven by turf battles between the Sinaloa and Jalisco New Generation cartels, in addition to other groups.

In June last year, the city’s mayor, Montserrat Caballero, announced she had decided to live at an army base for her own safety after receiving threats.

Earlier, Daily Mail Australia revealed that Callum's devastated girlfriend Emily Horwath shared a heartfelt tribute on social media.

'You are one of one,' she captioned a photo of the couple sharing a kiss. 

'I will love you forever.'

Mexican authorities said bandits attacked the three to steal the tires off their truck before killing them all and dumping their bodies in a disused well

The style of the executions have sparked fears locally about the possible involvement of drug cartels which are rife in the region (pictured: the trio's vehicle was later found burnt-out in the Santo Tomás area)

It took rescuers up to 20 hours to pull the bodies out of the well  (pictured)

She also posted an Instagram story which said: 'My heart is shattered into a million pieces, I don't have the words right now.'

'This world lost one of its kindest, silliest and most genuine of souls this week. Rest easy. I miss you.'

The US-based couple had travelled from their home in San Diego to Australia over Christmas and New Year, and shared photographs from Melbourne and Perth.

The three men had been on a surfing trip down Mexico's west coast. 

The three men were about 90 minutes' drive south of the US-Mexico border when they disappeared just a few days into the trip.    

In social media posts shared by Callum just before they vanished, the trio was seen relaxing at Rosarito Beach, where they were said to be surfing and camping as they moved up and down Mexico's west coast.

Callum's girlfriend Emily Horwath shared a heartfelt tribute on social media (the couple are pictured together on a recent trip to Australia) 

They reportedly planned to move on to Ensenada, about 50 miles (80km) down the coast, but concerns were raised when they failed to check into an Airbnb on Sunday.

Police said they found three abandoned tents south of Ensenada, which were splattered with blood, according to local media.

The brothers' mother issued a desperate plea on social media after the group failed to turn up at an Airbnb they had booked in Rosarito.

Mexican authorities also found shell casings at the campsite where the three men were last seen with further investigations leading them to the well about 2km away.

Three bodies, as well as a fourth body believed to be a local rancher, were discovered on Saturday in the clifftop well overlooking the ocean.

It is believed the rancher's body had been there for much longer and his death is not believed to be linked to the three young men.  

Brothers Jesús Gerardo Garcia Cota and Cristian Alejandro García were two of the three arrested. It is unclear which brother is which in their mugshots

Ari Gisel García Cota, 23, is one of three suspects arrested. She is reportedly the partner of Jesús Gerardo Garcia Cota, who was also arrested

It took rescuers up to 20 hours to pull the bodies out of the well, with physical characteristics, including hair and clothes, matching the three men.

It comes as Attorney-General María Andrade Ramírez said the murder investigation would probe whether the men were killed in an attempted robbery.

She said the thieves were likely interested in the mens' truck, a white Chevrolet Colorado pickup, and more specifically in the tires.

'The probability that it's them is very high,' Andrade Ramírez said.

'When they tried to get the vehicle, the victims opposed the robbery, the robbers were armed with a firearm and apparently shot the victims.'

Ms Ramirez added that the victims 'all have a hole in their head made by a firearm projectile'.

The Robinson brothers attended Coachella before going to Mexico to surf. Callum was based in the U.S. where he was a lacrosse player known as 'the Big Koala', and Jake, who worked in regional hospitals across Australia, had flown out two weeks ago to visit him 

Three Mexicans, Jesus Gerardo Garcia Cota, alias El Kekas, his girlfriend, Ari Gisel Garcia Cota, and his brother, Christian Alejandro Garcia, were arrested on Wednesday and charged with forced kidnapping.

Ms García Cota, 23, reportedly had one of the missing men's mobile phones.

It is understood police were able to make the arrests after one of the brothers' mobile phones was turned back on, and pinged a local mobile tower.

All three suspects were found in possession of an assortment of methamphetamines and other illegal drugs, according to local outlets Zeta and Talk Baja.

Baja California, where the men shared their vacation snaps, is known as one of Mexico's most violent, cartel-controlled states.

The Robinson brothers had attended Coachella before going to Mexico to surf.

Callum was based in the U.S. where he was an accomplished lacrosse player known as 'the Big Koala', and his brother Jake, who worked in regional hospitals across Australia, had flown out to San Diego two weeks ago to visit him.

Rhoad worked in technology services in San Diego.

READ MORE: Guilt-ridden friend reveals twist of fate that saved him from same grim end as two Aussie brothers killed in Mexico - and the hand-drawn map that blew the case wide open 

Randy Dible, a photographer from San Diego, feels guilty for recommending Callum stay on a remote stretch of coastline renowned for its surf breaks in Baja, Mexico