Smugglers ran their fast boat aground on a beach near La Linea and set it alight before fleeing on foot.
The rigid-hull inflatable boat, of a type commonly used to ferry drugs across the Strait of Gibraltar, was likely torched to destroy fingerprints and DNA evidence.
It was abandoned on a stretch of beach between Alcaidesa and La Linea early this morning.
Minutes earlier, the vessel had been photographed traveling at speed close to shore, although it was not being chased.
For hours it smouldered on the beach, drawing attention from curious passers-by.
Guardia Civil officers also attended the scene around two hours after the vessel was beached.
But this evening, as the sun set, the RHIB remained smouldering on the shoreline.