Spanish police are investigating three Irish nationals posing as tourists who are believed to have stolen thousands of euros with a “sob-story” scam.

The Catalan police force said that the men, aged between 19 and 35, had been operating in Barcelona, pretending they were holidaymakers who were unable to return home because they could not withdraw cash. They asked passersby for money, which they offered to repay immediately via bank transfer.

“The perpetrators show a receipt on their mobile phones for a transfer that will never actually go through,” said the police.

In May, one of the men, named by police as Martin Joseph S, aged 31, was arrested, and another, aged 19 and whose name has not been released, was detained last week. Both men, who were each responsible for conning at least eight people, the police said, were released pending judicial procedures. The third man, who remains at large, is believed to have robbed 15 people.

The second arrested man is believed to have operated near Sants railway station and in the central Eixample district of Barcelona and made at least €13,000 through the scam.

After his arrest, he had his passport confiscated. However, suspecting he might attempt to leave the country after his release, the police followed the Audi car with a UK number plate he was driving. Near the French border, his car had a puncture, at which point he appeared to realise that he was being tailed, abandoned the car and escaped on foot. Police believe all three men may have left Spain by now.

Some of the fraud victims took photographs of the suspects and several of these images have been published in Spanish media. Police believe that some or all the men may be related.

The Catalan police have issued a warning on social media about “false transfer” crimes, which they say are a new form of conning people.

“Don’t believe emergencies. And never give personal details or money to an unknown person,” said a police video.