ROME (AP) —

After months in a Rome jail, a pair of boyhood pals from California went on trial Wednesday, accused of murdering an Italian policeman during a summer vacation in Italy.

The Carabinieri paramilitary officer, Deputy Brigadier Mario Cerciello Rega, was unarmed and on plainclothes assignment with his police partner when he was stabbed 11 times and left bleeding on a street near the Americans’ hotel in the early hours of July 26, 2019.

Prosecutors have alleged that Finnegan Lee Elder, now 20, thrust an 18-centimeter (7-inch) attack-style knife repeatedly into the stocky police officer, while Gabriel Natale-Hjorth, now 19, scuffled nearby with the partner, Andrea Varriale, who was slightly injured.

Under Italian law, accomplices to an alleged murderer can also be charged with the murder itself. In addition to the murder charge, both defendants are also charged with attempted extortion related to a a drug deal gone bad, and resisting public officials.

Both defendants have said they thought they were being attacked and acted in self-defense.

Elder’s lawyers and family members have quoted the young man as saying that he had taken the two officers for a pair of common criminals out to assault the Americans and that he was fighting for his life.

According to judicial documents from early in the case, Natale-Hjorth claimed he didn’t know his friend had the knife. Prosecutors contend that after the stabbing, Natale-Hjorth hid the knife behind a panel in the ceiling of the hotel room the young men were sharing.