Finnegan Lee Elder, who was 19 at the time, was accused of repeatedly stabbing officer Mario Cerciello Rega in the early hours of July 26, 2019 while on holiday in the Italian capital, and Christian Natale-Hjorth, then 18, was accused of hiding the knife.
In Italy, accomplices can be charged with murder even if they weren’t directly involved.
Elder had admitted to stabbing Cerciello Rega, 2019, while Natale-Hjorth was wrestling with another police officer, Andrea Varriale.
However, the pair said they had acted in self defence because they thought the two police officers, who were not in uniform at the time, were thugs out to get them after a botched attempt to buy drugs.
After an unsuccessful attempt to buy cocaine, the two Americans stole a backpack belonging to a man said to have brokered that drug deal, then demanded money for its return.
Cerciello Rega was killed after he and his partner were dispatched to retrieve the backpack.
Elder repeatedly stabbed him with a seven-inch military-style knife after they began fighting.
Varriale, 27, has repeatedly stood by his account that he and his partner identified themselves as police officers as they approached the teenagers.
When he took the stand last July, he said that they had pulled out their badges and clearly announced themselves.
The court rejected the Americans’ testimony and handed down the toughest punishment possible in Italy.
Under Italy’s penal code, criminals serving a life term can be eligible for parole after 21 years, if they have a good behaviour record.
The two Americans, who come from San Fransisco, were also found guilty of attempted extortion, assault, resisting a public official and carrying an attack-style knife without just cause.
The pair were led out of the courtroom as soon as the sentence had been read out.
Cerciello Rega’s wife, clutching a photograph of her dead husband, was also in court and sobbed after the verdict was announced.
