The two young American men suspected in the stabbing death of a Carabinieri paramilitary officer in Rome last July began their trial today, and one or both of them face possible life sentences in Italian prison.

Finnegan Lee Elder of San Francisco, who has turned 20 since the crime occurred, is believed to have stabbed 35-year-old Deputy Brigadier Mario Cerciello Rega repeatedly with a seven-inch blade, because he believed he and his friend were under threat by a pair of Roman drug dealers on the morning of July 26, 2019. As the story goes, Elder and Gabriel Natale-Hjorth of Mill Valley, now 19, had arrived at a rendezvous with someone they thought was a dealer they had met earlier who jilted them in a cocaine deal. And the pair of Americans stole the man's backpack, and were meeting up to return the bag and retrieve a gram of coke.

As we now learn via the Associated Press, the dealer was actually a go-between for a bigger drug dealer, and he was also a police informant. So, when his backpack and cellphone were stolen, he reported it to the cops, and the cops sent two plainclothes, unarmed officers, Rega and partner Andrea Varriale, to deal with the situation and meet with the Americans.

The defense is expected to argue both that Natale-Hjorth was unaware that his friend even had a knife, and that Elder believed he was acting in self-defense when the two plainclothes officers approached them — not knowing that they were police, or that they unarmed.

Italian authorities later disciplined two police officers who blindfolded Natale-Hjorth during his interrogation and leaked the photos to the media.

The story made national headlines after the arrests of the two young men last summer, and drew comparisons to the Italian trial of American college student Amanda Knox, who was accused along with her boyfriend in the 2007 of their roommate and fellow exchange student Meredith Kercher. Knox was ultimately acquitted of the crime after eight years of trials and appeals.

Elder and Natale-Hjorth are both being tried for murder because under Italian law, an accomplice can be charged with murder even if they didn't have a direct hand in it.

It's not known how long the trial is expected to last.

Previously: Teen Accused In Killing Italian Cop Was Known To Attend 'Fight Nights' In SF, Injured Fellow High School Student