LONDON (AP) – As he lay dying, an ex-Soviet spy poisoned in London named an alleged Russian agent he feared had been targeting him and who he had previously told police was harassing him, a British newspaper said in a report published Sunday.

Alexander Litvinenko, a former KGB agent and fierce critic of Russian President Vladimir Putin, died Thursday night of heart failure after suddenly falling gravely ill from what doctors said was poisoning by a radioactive substance.

Litvinenko alleged that a Russian Foreign Intelligence Service chief previously stationed in London had been assigned by Moscow to watch him, Britain’s Sunday Times newspaper reported.

Litvinenko, who spoke to friends and dictated a vitriolic statement about Putin’s government while in the hospital, claimed the Russian agent was not directly involved in his poisoning, but had been sent to monitor his activities, the newspaper said.

London’s Metropolitan police said it could not immediately confirm whether officers would seek to find and interview the alleged Russian agent named by Litvinenko.

Police said anti-terrorist officers investigating the former agent’s death had not found records of earlier harassment complaints during their inquiry. An audio recording of Litvinenko making the allegation was being handed over to officers, the Sunday Times reported. Police said no tape had yet been received.

Russia’s Embassy in London said it could not immediately comment on the claims. Britain’s Foreign Office could not immediately confirm if a diplomat of the name used by Litvinenko had been based in London.

“Whilst in hospital Alexander named the man he alleged was watching him and said he had been the SVR (Russian Foreign Intelligence Service) station chief in London until 2003, posing as a diplomat at the Russian embassy,” Litvinenko’s friend Alex Goldfarb told The Associated Press.

Litvinenko, 43, told police he believed he had been poisoned on Nov. 1 while investigating the October slaying of Russian journalist Anna Politkovskaya, another critic of Putin’s government.

His contaminated body was released to a coroner by police Saturday and government pathologists were expected to begin an autopsy – though nuclear experts claimed investigators may never pinpoint the exact source of the rare radioactive polonium-210 element found in the ex-spy’s urine.

Britain’s Health Protection Agency said the poisoning was “an unprecedented event.” Traces of radiation were found at Litvinenko’s north London house, a sushi bar where he met a contact on Nov. 1 and a hotel he had visited earlier that day, police said.

British detectives investigating his death launched an international hunt for witnesses Saturday and spooled through hours of security video for clues. They were examining closed-circuit television footage and interviewing hotel and restaurant staff, a police spokeswoman said.

In a dramatic deathbed statement, Litvinenko accused Putin – who he called “barbaric and ruthless” – of ordering his poisoning. Putin has called the death a tragedy and denied involvement.

In other interviews before his death, excerpts and footage of which were released Saturday, Litvinenko claimed he had been ordered to hire assassins to kill rivals of Kremlin-favored business leaders and execute whistle-blowers who threatened to expose corruption.

Litvinenko spoke to academics James Heartfield and Julia Svetlichnaja from the University of Westminster in three interviews that lasted a total of about six hours in April and May. The Daily Telegraph published a syndicated version of the interviews Saturday.

Litvinenko was recruited into the Soviet-era KGB and also worked for its successor, the Federal Security Service, or FSB. He was later promoted to a specialist counterterrorism and organized crime unit. After the fall of communism, he said his directive was to recruit powerful businessmen who could stimulate an economic boom, and to hire assassins.

“Our department worked on the so-called problem principle – the government had a problem and we had simply to deal with it,” Litvinenko said in interviews.

By 1997, the department carried out “extralegal executions of unsuitable businessmen, politicians and other public figures,” he said.

In an interview recorded in late 2005 with British television journalist John Coates, excerpts of which were broadcast on Britain’s Sky television Saturday, Litvinenko said he raised concerns in 1997 with Putin – then head of the FSB.

Litvinenko publicly accused his superiors in 1998 of ordering him to kill Russian tycoon Boris Berezovsky, who was living in exile in London. He spent nine months in jail from 1999 on charges of abuse of office. Litvinenko was later acquitted and moved to Britain which granted him asylum in 2000. He recently became a British citizen.

The Kremlin had no immediate comment Saturday on the interviews.

Moscow’s government newspaper Rossiiskaya Gazeta pointed suspicion Saturday at London’s community of Russian exiles. Litvinenko “made his choice and drank his poison … when he betrayed those he worked for,” the newspaper said.

The newspaper speculated that Berezovsky was involved, aiming either to use the death to discredit Putin’s government or settle a business dispute. A presenter on Russia’s state-run Channel One television channel said there was “a theory (that) Litvinenko poisoned himself.”

Litvinenko was hospitalized last week after his hair fell out, his throat became swollen and his immune and nervous systems were severely damaged.

Polonium-210 can be found in Russia, which has several nuclear research facilities and a major space program, but Kremlin intelligence agents would be unlikely to use it since the origin could be traced, said Alexander Pikayev, a senior analyst with the Moscow-based Institute for Global Economy and International Relations.

Vladimir Slivyak, a nuclear expert and co-chairman of the Russian environmental group Ecodefense, said the material could have been acquired on the black market.

Leonid Nevzlin, a Russian exile in Israel, suggested in a statement that Litvinenko’s death was connected to information he had linking the Kremlin to the Yukos affair.

“Alexander had information on crimes committed with the Russian government’s direct participation,” Nevzlin said. “He only recently gave me and my attorneys documents that shed light on most significant aspects of the Yukos affair.”

Nevzlin said he relayed the documents to British investigators.