MEXICO CITY (AP) — Two Australians and an American were doing what they loved on the stunning, largely isolated stretch of Baja California’s Pacific coast. Their last images on social media showed them sitting and gazing at the waves, contemplating the breaks.

What happened to end their lives may have been as random as a passing pickup truck full of people with ill intent. The surfers were shot in the head, their bodies dumped in a covered well miles away. How it unfolded was the stuff of nightmares.

Brothers Jake and Callum Robinson from Australia and American Jack Carter Rhoad had apparently stopped to surf the breaks between Punta San José, about 50 miles (80 kilometers) south of Ensenada, and La Bocana, further north on the coast. They were attacked there on April 28 or 29.

As soon as police arrived at their last known camp site, it was clear that something had gone violently wrong.

There were bloodstains and marks “as if heavy objects had been dragged,” leading to suspicions of an attack, the Baja California state prosecutor’s office said in an attempt to reconstruct the scene.