Former Russian spy Alexander Litvinenko is believed to have been working with the British secret service when he was murdered in 2006, according to new evidence presented in a preliminary inquest into his death in a London court.

Litvinenko, who was poisoned with the radioactive isotope polonium-210 and died in November  2006, was reportedly receiving payments from the U.K.’s MI6 at the time, as well as from the Spanish secret service.

Other documents were also presented that indicated the involvement of the Russian government in Litvinenko’s death, the BBC reported.

Moscow has denied any involvement in the death of the former KGB agent, who, on his deathbed, accused the Russian government, naming President Vladimir Putin in particular for orchestrating his assassination.

Litvinenko had reportedly met in London with former KGB contacts Andrei Lugovoi and Dmitry Kovtun. Lugovoi remains the primary suspect in Litvinenko’s murder, but Russia has refused to extradite him for questioning.

The official inquiry is set to begin May 1, 2013, and will determine London’s official position on Livinenko’s death.

Ben Emmerson, a lawyer representing Litvinenko’s widow, has asked the court to consider whether MI6 failed in its responsibility to protect Litvinenko against a “real and immediate risk to life” based on the evidence supporting his connection to the agency, the BBC reported.

The British government has yet to officially confirm that Litvinenko’s was on the MI6’s payroll.

It was also revealed that Litvinenko was in contact with Spanish intelligence agents and had planned to travel to Spain to help the Spaniards monitor the Russian mafia’s activities there.