Update: One of the teens accused of killing Italian officer left a student with severe brain injury during 2016 fight [Report]

One of the two American teens accused of killing an Italian police officer in Rome, Italy, last week, was apparently in a previous altercation that left a teen in the hospital with a serious brain injury, according to a source familiar with the incident.

San Fransisco Chronicle reports that Finnegan Lee Elder, 19, (pictured left) one of the two teens accused of killing 35-year old Carabinieri officer Mario Cerciello Rega, was reportedly in a fight at a high school party in 2016. Finnegan punched and injured a 16-year-old Sacred Heart Cathedral Preparatory student in the head, injuring the victim to the point that he required hospitalization.

Elder graduated from Tamalpais High School in San Fransisco, but previously attended Sacred Heart with the victim. Both boys were at a party held in a park off of Sloat Boulevard and 19th Avenue when the incident occurred. At the time, police said the victim had “life-threatening injuries,” but he eventually healed and now attends college.

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Elder was arrested on suspicion of battery, but since his case was handled in juvenile court, it’s unclear what type of punishment he faced. San Francisco police, along with the DA’s office declined to comment on the case.

The teen’s uncle, however, told the outlet that the fight was “agreed upon” in advance and egged on by football players. The uncle said the boy was not disciplined by his previous school and transferred to another high school only because the family moved.

“I’ve known Finn for his entire life and have never seen him be violent, or even lose his temper,” the teen’s uncle, Sean Elder, said.

As CrimeOnline previously reported, Elder and high school friend Gabriel Christian Natale-Hjorth, 18, were spotted fleeing the scene after Rega was stabbed 11 times Friday night.

Authorities later found “overwhelming evidence” inside the teens’ hotel room in the Prati neighborhood of Rome, according to ABC7, which reportedly included bloody clothing and the hidden murder weapon.

Both teens were later detained, while one was apparently blindfolded and handcuffed. The viral photo made its way across social media, prompting Italian authorities to issue a statement indicating they were in the wrong for covering the suspect’s eyes.

The New York Times reports that both teens admitted they were in an altercation with Rega.

According to police, the suspects bought drugs from an Italian man on Friday, after a man identified as Sergio Brugiatelli led the “blonde youth,” identified as Natale-Hjorth, to a drug dealer while Elder sat on a bench close to Brugiatelli’s backpack.

The teens reportedly claimed the drugs “weren’t real.” In turn, Elder allegedly grabbed Brugiatelli’s backpack with his cellphone inside and fled. When the man called his phone, one of the teens answered and demanded “100 euros and a gram of cocaine” for the return of the backpack.

The pair reportedly arranged to meet  Brugiatelli and exchange the backpack for money and drugs, but unbeknownst to them, the man called the police and reported the alleged theft. When the suspects showed to up the arranged meeting place, Rega was there with the backpack, along with his partner, officer Andrea Varriale.

A fight apparently broke out and the officer was left with multiple, fatal stab wounds.

According to CBS, Elder, who appeared in court on Monday, told Italian Judge Chiara Gallo that Rega was strangling him and he acted in self-defense. The teen also reportedly said he didn’t know Rega was an officer and thought he was Brugiatelli’s friend.

Elder said Rega never identified himself but Varriale said both teens attacked them before they had a chance.

“But the pair, even before we could carry out any kind of check, attacked us physically,” Varriale reportedly said.

Natale-Hjorth reportedly claimed he didn’t see his friend stab Rega. He allegedly said he returned to the hotel and took a nap, and Elder later told him he used a knife on the officer when he woke up.

Both suspects were charged with murder and denied bond. They’re being held at the Regina Coeli prison and could face life in prison if convicted.

Meanwhile, Rega was laid to rest on Monday in the same church he got married at. The newlywed had been married a little over a month before the tragedy occurred. The crowd of mourners grew larger than the church could accommodate. Numerous people lined up outside the church to mourn the beloved officer.

The story continues to develop. Check back with CrimeOnline as additional details become available.

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[Feature Photo: Finnegan Elder (L) and Gabriel Christian Natale-Hjorth (R)/Police Handout]