Aleksandr Litvinenko, a former agent in Russia's Federal Security Service, lies in a London hospital, critically ill after apparently being administered a potentially lethal dose of the poisonous metal thallium.
Alex Goldfarb, an acquaintance of Litvinenko, visited him on November 18 and described his condition.
"I saw him last yesterday and he looks like a ghost. He lost all his hair, he has a kind of a red mouth because he has an inflammation in his mouth," Goldfarb said. "He looks like a cancer patient who went through heavy chemotherapy. And just a month ago he was a fit, young, handsome guy."
It has been nearly three weeks since Litvinenko fell ill. Officials at London's University College Hospital today described his condition as "serious but stable."
Doctors say the 43-year-old Litvinenko is suffering the effects of the toxin thallium, an ingredient in rat poison that attacks the nervous system and lungs.
Litvinenko became violently ill just hours after meeting with a man who purported to have information regarding the October 7 killing of Russian journalist Anna Politkovskaya.
Litvinenko became violently ill just hours after meeting in early November with a man who purported to have information regarding the October 7 killing of Russian journalist Anna Politkovskaya.
He described the meeting in an interview November 11 with RFE/RL's Russian Service.
"A person made himself known to me and proposed that we meet so that he could give me some information, including details about the people who murdered Politkovskaya," Litvinenko said. "It was November 1. I met with this person; he and I sat in a restaurant, and he gave me some papers. I went home and in a couple of hours I felt sick; I was struck by an extremely bad case of poisoning. Now I'm in the hospital."
David Leppard, an investigative journalist with Britain's "Sunday Times" newspaper who has met with Litvinenko and reported extensively on the poisoning case, told RFE/RL he has spoken to a wide range of medical officials about Litvinenko's case -- including toxicology expert John Henry, who examined Ukrainian President Viktor Yushchenko after his apparent poisoning with dioxin two years ago.
His conclusion, he says, is that the former spy was "deliberately poisoned" by "persons unknown."
"Thallium is a drug which can be ingested into the human body not just by food or liquid; it can also be put into the blood through rubbing on the skin and other means," Leppard says. "But it does take several hours for the effects of the drug to occur. So it is possible that Mr. Litvinenko has been poisoned by somebody other than the person whom he met at the Japanese restaurant in Picadilly on November 1. But it seems certain that he was poisoned on that day."
Litvinenko, who defected to Britain six years ago, had angered the Kremlin in the past with allegations that his FSB superiors had ordered him to assassinate Russian tycoon Boris Berezovsky, a longtime Kremlin foe.
He has since written a book accusing the security service of orchestrating a 1999 spate of apartment-block bombings in Moscow and other cities, which killed hundreds of people.
The Kremlin attributed the blasts to Chechen separatists and used them as a pretext for launching the second war in the North Caucasus republic.
Litvinenko also suggested the 2004 Beslan school siege may have been carried out on FSB orders.
The FSB has categorically denied any role in Yandarbiyev's killing and has rejected the rest of Litvinenko's claims as well.
But Goldfarb and others believe the security service is behind Litvinenko's poisoning.
"When I saw him I thought that they finally got him, as they have been threatening for the past seven years when he started irritating the Russian government and the Russian secret services with his work and his statements," Goldfarb said.
Oleg Gordiyevsky, a London-based officer with the FSB's predecessor agency, the KGB, is the highest-ranking KGB official ever to defect.
Speaking to RFE/RL from London, he says he has no doubt the FSB is behind the attempt on Litvinenko's life.
"Litvinenko had received numerous threats from the KGB during these four years here. This was clearly organized at a governmental level, that is by the KGB," Gordiyevsky says. "He was always waiting for an attack by the KGB, and from no one else. So this makes perfect sense. This is a KGB poison, this is not a readily available poison; you can't buy thallium in pharmacies and they won't give it to you in hospitals either. This was a pure KGB operation."
Deputy Kremlin spokesman Dmitry Peskov today dismissed allegations that Moscow was involved in the poisoning, calling such suggestions "nonsense." Sergei Ivanov, a spokesman for Russia's Foreign Intelligence Service (SVR), told AFP his country's secret services "have not carried out poisonings or any form of assassination in a long time."
London's metropolitan police have opened an investigation into the poisoning.
Some attention has focused on the man who met on November 1 with Litvinenko in a London sushi bar.
Mario Scaramella is an Italian professor believed to have close ties to the Italian and Russian intelligence services.
He apparently spoke to British Embassy officials in Rome after hearing of Litvinenko's poisoning. But his whereabouts and his role in the incident have not been publicly disclosed.
Litvinenko said the papers given him by Scaramella appeared to offer critical details about the murder of Politkovskaya, a vocal critic of Kremlin policy in Chechnya.
"They were in English, and I didn't get to go through them very thoroughly," Litvinenko said. "But there was information that pointed to a person who was possibly the one who killed Anna Politkovskaya. It said the man was an officer with the Russian special services, who was serving in the Caucasus."
Litvinenko has said he intends to pass the papers to Politkovskaya's "Novaya gazeta" newspaper as soon as he recovers.
Editors at "Novaya gazeta," however, have told RFE/RL they are conducting their own research into the case, in addition to following the official investigation, and will not leap to judgment about who is responsible for Politkovskaya's death.
KGB defector Gordiyevsky says he believes Scaramella is in no way connected to Litvinenko's poisoning -- or to the Politkovskaya investigation. The attempted assassination, Gordiyevsky said, is part of a broader "campaign against dissidents."
"I personally consider that this case is in no way connected to the investigation into Politkovskaya. The fact is that this Mario is very fussy, very active -- Mario Scaramella, I know him well," Gordiyevsky says. "He dug up some document somewhere that he considered important and shoved it on to Litvinenko, who was already starting to feel sick. Litvinenko reads English badly, he didn't even read it. It's absolutely not important, because he'd already been poisoned."The Litvinenko poisoning is reminiscent of past Soviet-style skullduggery, including the assassination in 1978 of Bulgarian dissident and former RFE/RL freelance journalist Georgi Markov, who was killed in London with a poison-tipped umbrella.
More recently, Ukraine's president, Viktor Yushchenko, was badly disfigured with an apparent case of dioxin poisoning that he said was the work of political opponents. That case has yet to be solved.