Spanish police have detained a 42-year-old man, believed to be Irish, on suspicion of stabbing two women to death in their Costa del Sole homes, according to the Spanish TV station Telecinco.

It is believed detectives were treating the Irishman as a suspected serial killer as they attempt to link him to a series of unsolved murders across Spain.

Local media have identified the man as Irish but it understood that documents he was carrying when he was arrested  were fake.

One of the cases involved a 45-year-old Spanish woman of Argentine origin who was found in her Costa del Sol apartment on August 11, after being stabbed 15 times.

One month later police in the region found a 47-year-old Ecuador-born woman at her rented home near Marbella. She died from hemorrhaging after being stabbed up to 12 times in her chest and neck.

Both of the victims were identified as prostitutes.

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A spokesman from Spain's National Police and Civil Guard were unable to confirm the suspects name and nationality, as the investigating judge as granted a secrecy order on the case.

A spokesman for the National Police said: "I've seen the reports suggesting the suspect is Irish and I've also seen other newspaper reports he's from central Europe, but I cannot give you any details about the man who is in custody."

The man was arrested on Friday at a gym close to his home in Riviera del Sol near Fuengirola. His Moroccan girlfriend and her mother were also detained.

A spokesperson from the Department of Foreign Affairs told the Evening Herald that they had received "no request for consular assistance".

Spanish police arrest 'Irish serial killer’