Facebook has come to the aid of a man accused by Italian prosecutors and British police of being one of the world’s most wanted people smugglers, providing electronic data that suggests the detainee is a victim of mistaken identity.

Last June, Italian and British officials claimed to have captured Medhanie Yehdego Mered, alleged to be responsible for smuggling of thousands of people from north Africa to Europe.

After being extradited from Sudan to Italy, the man alleged to be the smuggler faced two prosecutions, first in Sicily and then in Rome, despite a series of Guardian articles that revealed doubts about the identity of the man in custody. Evidence uncovered by the Guardian suggests the man being held is Medhanie Tesfamariam Berhe, an Eritrean refugee with no connection to Mered’s alleged smuggling business.

On Tuesday, following a request by Berhe’s lawyer, Facebook gave the court in Palermo a file containing details of Berhe’s Facebook profile, including IP addresses and access to the account of the accused.

The prosecutors are trying to prove the accused was in Khartoum in Sudan in 2013 and to back up that claim have said he was using his Facebook account while he there. But Facebook data contradicts this, and shows that the first access to the account in question is dated October 2014 in Eritrea, and then Ethiopia, in a refugee camp. The first access in Sudan is dated 2015, as Berhe has always told the court.

“This shows that my client is not a liar,” Michele Calantropo, Berhe’s lawyer, told the Guardian. “It proves Medhanie Tesfamariam Berhe was in Eritrea while the prosecutors were wiretapping the real smuggler Medhanie Yehdego Mered in Khartoum.”

“My client is no people smuggler,” said Calantropo. “He is a refugee. They got the wrong man. And I really hope prosecutors are going to admit their mistake as soon as possible because an innocent man has spent almost nine months in jail. And this is unfair.”

The Facebook disclosure follows a series of other developments that cast doubt over the claims of the UK’s National Crime Agency (NCA) and the Italian prosecution. The file also contained details of two other Facebook accounts, both belonging to the alleged real smuggler Mered – the same profiles prosecutors used two years ago during their initial investigation. The electronic trail of these two accounts shows that Mered has been travelling from Sudan to Libya, and then back to Sudan and Dubai, where the “social smuggler” is still posting videos and pictures.

Among those details, the Guardian found the smuggler’s mobile phone number. The sim card is from Dubai, where the human trafficker is believed to be in hiding and where the British and Italian police believe he was doing business.

Although the Guardian was unable to reach the user, a message delivered through WhatsApp showed that the user, possibly Mered, was online and had accessed WhatsApp at least four times during the day.

The account also displayed a photograph of a bar in Dubai – the same photo displayed on the real Mered’s Facebook account. The phone number listed on the Facebook page and on WhatsApp matched the one associated with Mered on Italian court documents. Last November, the Guardian published the content of a private post from one of these two profiles, where the smuggler, in private messages sent from his Facebook account and later seen by the Guardian, said the man “arrested in his place is the victim of mistaken identity”.

The NCA and Italian prosecutors declined to comment until the court case is concluded.