Two Americans arrested in connection with the death of an Italian paramilitary officer had blamed each other for committing murder, court documents sent to reporters show.

Gabriel Christian Natale-Hjorth, 18, and Finnegan Lee Elder, 19, both from Mill Valley, California, were detained by police in Rome on Friday for alleged homicide and attempted extortion.

Police have said the pair had a violent encounter with two plainclothes members of the storied Carabinieri paramilitary corps, after having stolen a backpack from an Italian national and demanded money and a gram of cocaine in exchange for its return.

On Sunday, police released audio files of two calls with the Italian national who allegedly had his backpack stolen. He alleged he had spoken to the people who stole his bag by calling his cellphone, which had been inside the bag, adding that the suspects demanded money for the return of his belongings.

The dispatcher agreed to send an officer to meet the victim.

Mario Cerciello Rega, 35, who had just returned to duty a few days earlier from his honeymoon, was dispatched on Friday to meet with the Americans as part of the investigation, authorities said.

A detention order says Natale-Hjorth, who can understand Italian, confirmed that Rega identified himself as a Carabiniere officer. Elder, who doesn't speak the language, denies the officer revealed who he was.

The encounter quickly turned deadly with a violent struggle that resulted in Rega's stabbing. The pair then fled to their hotel room at the four-star Le Meridien, where police found them hours later, the order says.

When separately interrogated, each suspect blamed the other for the stabbing, according to the document. However, Elder had recognized the weapon — a large knife seized from their hotel room — as his own and also confirmed it was the murder weapon, the document says.

The detention order requires the men to be detained in isolation and forbids them from meeting. It also deems them a flight risk because they are foreign citizens.

A leaked photo that appears to show one of the men in police custody, blindfolded and handcuffed while sitting with his head bowed, is being investigated by police.

In a phone interview with the Associated Press, Provincial Cmdr. Francesco Gargaro confirmed the photo's authenticity and added that blindfolding a suspect is illegal.

The officer who put the blindfold on committed a “mistake” but did so to prevent Natale-Hjorth from seeing documents related to the investigation, the commander said. The officer has been transferred to a different unit.

Italy's Deputy Prime Minister Matteo Salvini tweeted that anyone concerned about the treatment of those arrested should remember the only real victim is the officer who died. He added that if the suspects are found guilty, they deserve life in prison.

Elder's family issued a statement Sunday saying that they had not been able to contact their son since he called after his arrest. The family said they were working with the State Department to try and gain access to their son and that he was being represented by an Italian public defender.

"We plan to go to Rome as soon as the State Department assures us we will be able to see our son," the statement said. "We are also aware of the funeral plans for Officer Rega, and wish to be respectful of his family and friends at this devastating time."

Rega is expected to be buried on Monday after a public viewing is held on Sunday. It is unclear when the next court hearing will be scheduled.