Why were the three missing surfers killed in Mexico? What we know so far

Authorities are investigating how the three ended up dead at the bottom of a well and who killed them

The American from San Diego and his two friends – brothers from Australia – lived their dream by surfing and camping on the sun-drenched Mexican coast.

Callum Robinson, 33, posted pictures from the trip on Instagram, which showed him, his brother Jake Robinson, 30, and their American boyfriend, Jack Carter Rhoad, also 30, relaxing in the hot tub, eating tacos and drinking beer with their feet up.

That was before the unthinkable happened.

On Friday, the FBI San Diego announced that Rhoad, of San Diego, and Jake Robinson, of Perth, and Callum Robinson, also of San Diego, were found dead at the bottom of a 50-foot well in a remote part of Santo Tomas, Baja California, NBC San Diego reports.

Authorities said they were all shot.

The friends were last seen on April 27 while surfing and camping on the Mexican coast south of Ensenada.

They pitched tents and parked their white pickup truck nearby so they could surf the sky-blue waves.

But they weren’t alone out there.

“The attackers drove by in their vehicle,” María Elena Andrade Ramírez, Baja California’s chief prosecutor, said at a news conference on Sunday, CBS News reports.

“They approached her with the intent of stealing her vehicle and taking the tires and other parts to install on the older pickup truck they were driving,” she said.

Related: One of the surfers killed in Mexico got engaged in August

“When they (the victims) showed up and caught them, they certainly fought back,” she said.

“And these people, the attackers, got a gun and first killed the one who resisted the vehicle theft, and then others came and joined the fight to defend their property and their companion who was attacked, and they have them also killed,” she said.

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Investigators found a bullet casing, plastic gallon bottles, blood stains and drag marks in the area where the three men had set up camp, authorities said, CBS News reported.

Related: Authorities reveal how missing surfers from the US and Australia who were found at the bottom of a well in Mexico died

The attackers burned the tents, authorities said.

Authorities also found a burned-out white pickup truck that they believe belongs to Callum Robinson, CNN reports.

Police have arrested Jesus Gerardo, whose pseudonym is “el Kekas” and who has a criminal record, in connection with the case, CNN reports. It is not clear whether he has retained an attorney to comment on his behalf.

They are interviewing others, including a man and a woman, who “may be directly or indirectly related to this case,” Andrade Ramírez said, according to CBS News.

The authorities are still investigating.

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