Elder and fellow US student Gabriel Natale-Hjorth will stand trial next week in Rome over the killing of Mario Cerciello Rega, an Italian policeman who was in plain clothes when he was slain in a botched drug bust on July 26, 2019.
The two teens face life sentences if found guilty of knowingly killing a police officer.
In a leaked transcript of a secretly-recorded conversation in jail between Elder and his father, the student appears to say he had been aware that Cerciello, 35, was a policeman and had seen a police car, or in slang, a “tank”.
The recorded conversation “has been taken as proof they knew”, according to Elder’s lawyer, Renato Borzone.
But Borzone claimed the transcript prepared by police and handed over to prosecutors was “badly translated” and incomplete.
Alleged errors in the transcription included the word “tank”; Borzone claimed Elder instead said “bank”, making a reference to a landmark.
Borzone said he expected the transcript to be re-translated by a court-appointed, independent translator, adding that the leak to the press of the incorrect transcript had seen the two suspects risk a trial by media.
According to prosecutors, Elder, 20, has confessed to stabbing Cerciello Rega with a US Marine partially-serrated, close-quarters combat knife, claiming he thought the officer and his partner Andrea Varriale were dangerous drug dealers, and that he acted in self-defence.
Cerciello Rega and Varriale had been tasked with intercepting the American tourists after an intermediary on a drug deal reported them to the police for stealing his bag after they were sold aspirin instead of cocaine.
The officers were in plain clothes, but told the suspects that they were police.
But the teens, who were wearing hooded sweatshirts, claim they thought the men were dangerous drug dealers.
Cerciello Rega, who had recently returned to work from his honeymoon, had been carrying handcuffs, but not his gun, which he had left in the barracks after bringing colleagues ice cream earlier in the evening.
Elder, who was 19 at the time of the incident, says Cerciello attacked him from behind, while Varriale wrestled with Natale-Hjorth, 18.
Natale-Hjorth initially told investigators he had not been involved, but his fingerprints were found on the ceiling panel.
Under Italian law, anyone who participates even indirectly in a murder can face homicide charges.
The two are being held in Rome’s Regina Coeli jail.