An Eritrean man says his brother, believed one of the world’s most wanted people smugglers, remains free while another has been arrested in his place. Merhawi Yehdego Mered, 38, has testified before a judge in Palermo, via videolink from the Netherlands, saying the man facing trial in Sicily is not the notorious human trafficker Medhanie Yehdego Mered.

Merhawi suggested that the suspect, who has now been in prison for two-and-a-half-years, is a victim of mistaken identity. “This is not my brother,” he said when seeing the detainee on camera.

In June 2016 prosecutors in Palermo announced the capture in Khartoum of a 35-year-old Eritrean whom they alleged was Medhanie Yehdego Mered, AKA “the general”. He was suspected of being one of the most sought after human traffickers in the world, and he was extradited to Italy from Sudan with the help of the UK’s National Crime Agency.

His arrest, after an investigation that spanned two continents and five countries, was presented to the press as a brilliant coup for the new anti-trafficking strategy.

But since news of the arrest first broke there have been serious doubts over the man’s identity. Dozens of Mered’s alleged victims claim the wrong man is on trial. The man extradited also looks markedly different to photographs of Mered released by prosecutors before the arrest.

Close friends and relatives of the detainee have told the authorities that the man arrested is 29-year-old Medhanie Tesfamariam Berhe, a refugee.

Merhawi is the latest person to insist that the authorities have apprehended the wrong man. Last week, Lidya Tesfu, reportedly the trafficker’s wife, told the judge that the man in prison was not her husband. “I know you have placed my husband under investigation,” she said. “But the man on trial is not Mered.”

Among the many factors that point to the innocence of the arrested man, including two DNA tests (one of them carried on the smuggler’s son) is a documentary by the Swedish broadcaster SVT in collaboration with the Guardian, which said Mered was living it up in Uganda while Berhe faced up to 15 years in jail.

In July 2017 the New Yorker published an investigation based in part on a three-hour telephone interview with Mered. He told the magazine he was still at large and that he was in prison in a different country at the time of the Berhe’s arrest.

Last week a lawyer requested that Berhe be released on bail and placed under house arrest. The judge rejected that request, fearing that Berhe could flee the country before the verdict.

The NCA and Italian prosecutors declined to comment “until the conclusion of the court case’’.

The growing impression is that the prosecutors are no longer concerned whether the man in custody is Mered, but are intent on demonstrating that they have apprehended a man involved in smuggling. “It now appears obvious that Berhe is neither a trafficker nor an intermediary,” Berhe’s lawyer, Michele Calantropo, told the Guardian.

Berhe’s sister, Seghen Tesfamariam, said: “The trial is going unfairly. No matter what evidence the lawyer presents, they don’t want to accept it. The only way to sentence my brother for being Mered would be to fabricate the evidence.”

According to Fulvio Vassallo, an expert on migration and asylum law, from the University of Palermo, this case is more than a story of mistaken identity. “This endless trial, carried out on the basis of contradictory evidence, is the proof that the entire strategy pursued by EU governments of hunting down smugglers through criminal proceedings as a way to keep immigration numbers down is failing.”