Further details have emerged regarding the arrest of Jason Peter Marshall, a 24-year-old man from Greenwich, south-east London, who was arrested on Friday in Italy on suspicion of murdering retired tour guide Vincenzo Iale and attempting to murder another man.

It’s claimed he met both men using gay chat rooms.

After meeting the unnamed 55-year-old man, Marshall accompanied him to his home in the Casal Morena neighbourhood of Rome on Thursday night, reports the Telegraph.

A police officer connected with the case said: “They ate dinner, watched TV and kissed but did not have sex.

“Then the victim noticed that Marshall was carrying a gun and demanded to know why.

“Marshall claimed to be working for MI5 and involved in security at the British embassy in Rome. When the victim did not believe him, Marshall flew into a violent rage.”

The victim claimed that Marshall then started to punch him repeatedly and tried to suffocate him with cushions.

“He tortured him for hours to get him to reveal his bank card code. Four hundred euros (£348) was also stolen from the apartment,” said the officer.

In addition to the money, he also stole the victim’s iPad.

Neighbours who heard the victim screaming called the police but the attacker fled before officers arrived.

The victim gave police Marshall’s phone number and it was used to determine his location.

He was tracked down on a bus in the suburbs of Rome at 3:30 am on Friday.

“He tried to flee but was blocked and gave himself up,” said the officer.

Police discovered that the gun Marshall had been carrying was a replica and he had attempted to erase traces of email contact between himself and the victim on the stolen iPad.

Marshall, who moved to Rome’s Prati district on 11 January, is also a suspect in the murder of a retired, 68-year-old Italian tour guide named Vincenzo Iale who he also met in a gay chat room.

He is suspected of having sex with Mr Iale before stabbing him four times in the chest and then strangling him with an electrical cord.