The 19-year-old suspects confessed after they were arrested for alleged murder and attempted extortion, police said. Italy's Interior Minister Matteo Salvini had vowed that those responsible "will pay in full."
Two US citizens have confessed to a fatal knife attack on a Carabinieri police officer in Rome, Italian police said on Saturday.
The 19-year-old suspects were arrested for alleged murder and attempted extortion after police found them hiding in a hotel room. They appeared in court in Rome on Saturday.
Mario Cerciello Rega, 35, was fatally stabbed in Rome's central Prati district near the Vatican early Friday morning.
Stabbed by muggers
Cerciello Rega and other officers were involved in a plainclothes operation against two muggers at around 3 a.m. local time.
The muggers had stolen a backpack from a man, later saying they would return his belongings in exchange for €100 ($110) and a gram of cocaine.
Cerciello Rega was known for helping out his community and his volunteer work, Italian media have reported
The man reported the crime and attempted extortion to the police and set up a meeting point with the thieves.
Police showed up to the meeting and were attacked with a knife. Cerciello Rega sustained eight stab wounds and later died of his injuries in hospital.
'Mario was a lovely lad'
The case has shocked Italy, with mourners coming to leave bouquets of flowers outside the police station where he worked.
Interior Minister Matteo Salvini expressed anger on Friday after police said the perpetrator was "probably an African citizen."
"I am sure that they will catch him, and that he will pay in full for his violence with forced labor in jail as long as he lives," the far-right politician tweeted. There are no provisions for forced labor in prison in Italy, according to news agency DPA.
During a television appearance on Friday morning, Salvini said, "Apparently they [the suspects] are not Italians. What a surprise!" and called the killer of Rega a "bastard."
Cerciello Rega had been married for just over a month when he was killed, and had recently celebrated a birthday.
"Mario was a lovely lad," Sandro Ottaviani, the commander of Rome's Piazza Farnese Carabinieri station, told ANSA. "He never held back at work and he was a figurehead for the whole district."
shs, rs/cmk (dpa, AP)