Investigators have identified several suspects in the murder of Russian opposition leader Boris Nemtsov, Russian news agencies reported Wednesday, citing Aleksandr Bortnikov, the head of the country’s Federal Security Service. Nemtsov was shot multiple times and died Friday night in central Moscow.

Authorities are probing several angles in the case, including a contract killing, Russia’s TASS news agency reported. The finance ministry reportedly said earlier on Wednesday that a car sought in connection with the case belongs to a federal state unitary enterprise (FSUE) providing services to Goznak, the Russian state body that prints banknotes, and other agencies. Earlier, local reports had stated that police were looking for a car that fled the murder scene and that the vehicle allegedly belonged to the Russian finance ministry.

"The Ford car we are talking about does not belong to the Finance Ministry," the ministry’s press service told TASS. "This is a vehicle of an in-house security service, an independent FSUE providing services to the Finance Ministry, Goznak and other bodies.

"At the moment the FSUE car was crossing the bridge, a patrol vehicle and police officers were already there," the ministry noted.

Nemtsov was reportedly walking over the Great Moskvoretsky Bridge near the Kremlin in Moscow with his girlfriend, Anna Durytska, when a man rushed out of a white car behind him and shot him four times.

“We should finally spare Russia from tragedies like one we’ve seen lately,” Russian President Vladimir Putin said, at an interior ministry meeting, according to Russia’s RT news. “I mean the brazen murder of Boris Nemtsov right in the center of the capital.”

Prior to his death, Nemtsov, a vocal critic of Putin, had been organizing an upcoming rally in protest of the conflict in eastern Ukraine, which Western powers have blamed Moscow of fomenting. The 55-year-old, who had received several death threats over the years, had expressed suspicion that Putin wanted him dead.

Nemtsov was buried at Moscow’s Troyekurovo cemetery on Tuesday and thousands attended his funeral. Russian opposition leader Alexei Navalny, who is serving a 15-day sentence in Moscow for organizing an unauthorized march and was barred from attending the funeral, held Russian authorities responsible for Nemtsov's murder.

"I believe that Nemtsov was murdered by members of a government (special services) or pro-government organization on the order of the country's political leadership (including Vladimir Putin)," Navalny said, according to BBC.