Rome — A new trial opened Friday for two American men in the slaying of an Italian plainclothes police officer during a botched sting operation after Italy’s highest court threw out their convictions.

Italy’s highest Cassation Court ordered a new trial last year, saying it hadn’t been proven beyond a reasonable doubt that the defendants, with limited Italian language skills, had understood that they were dealing with Italian police officers when they went to meet an alleged drug dealer in Rome.

Finnegan Lee Elder and Gabriel Natale-Hjorth, who were teenagers at the time of the July 26, 2019 slaying, sat side-by-side as an appeals court judge made opening remarks in the new trial. The two are being held in separate prisons near the Italian capital.

The friends from California were found guilty in the 2021 killing of Carabinieri Vice Brigadier Mario Cerciello Rega and four other counts and sentenced to life in prison, Italy’s harshest punishment. The sentences were reduced to 24 years for Elder and 22 years for Natale-Hjorth on appeal.

Prosecutors alleged Elder, who was 19 at the time, stabbed Cerciello Rega 11 times with a knife that he brought with him on his trip to Europe, and that Natale-Hjorth, then 18, helped him hide the knife in their hotel room. Natale-Hjorth testified that he grappled with Cerciello Rega’s partner and was unaware of the stabbing when he ran back to the hotel.

The two friends had arranged to meet a small-time drug dealer, who turned out to be a police informant, to recover money lost in a bad deal and return a backpack they had snatched in retaliation, when they were confronted by the officers.

Elder and Natale-Hjorth were school friends from northern California who were meeting up for a few days in Rome, where Natale-Hjorth had family.

The killing of 35-year-old newlywed Cerciello Rega shocked Italians, who mourned him as a national hero.