An Irishman is being questioned by Spanish police investigating the discovery of two bodies believed to be those of Dublin drug dealers Shane Coates (31) and Stephen Sugg (27).
It is believed he was arrested at his home near Catral, near Alicante in southern Spain this morning.
Garda Commissioner Noel Conroy confirmed the arrest and said it was up to the Spanish Guardia Civil to decide the whether any charges would be brought.
"We have gardaí in Spain at the moment who brought information to the Spanish authorities," the Commissioner said.
"They're investigating that. We know that an Irish citizen has been arrested in relation to the alleged crimes and the Spanish authorities will now deal with it as they see fit."
Mr Conroy added the information that led to the discovery of the bodies came from the gardaí.
Meanwhile, Spanish authorities are expected to carry out a post mortem today on two bodies recovered yesterday evening from a concrete covered grave around 30 miles south of the Alicante region on the A7 motorway to Murcia.
Coates and Sugg were leaders of the infamous Blanchardstown-based drugs gang the Westies and were abducted from their Alicante apartment 2½ years ago.Preliminary examinations show they were shot in the head.
They are believed to have been killed by a gang led by a Finglas criminal with whom they had been working in Torreviega, Alicante, in southern Spain.
Those who killed them had gone to extreme lengths to conceal their bodies. They had dug up a section of concrete, dug a six-foot grave, dumped the men's remains in it and then covered the grave again with concrete.
The two men had left Ireland after they had both been served with demands from the Criminal Assets Bureau totalling nearly €800,000. It is believed they hoped to set up an operation importing drugs from Spain into the Republic.