Poisoned spy Alexander Litvinenko described his suspected murderer as a "good friend" before introducing him to a man who the Russians believed was his "MI6 handler", an inquiry has heard.
Mr Litvinenko worked for Dean Attew, carrying out due diligence reports for his business, Titon - an international subsidiary of security company Erinys.
Giving evidence at an inquiry into the Russian dissident's death, Mr Attew explained that he first met Mr Litvinenko in 2004, but that he was not given any work until two years later.
Mr Litvinenko died on November 23, 2006, nearly three weeks after he drank tea laced with a radioactive substance in the company of two Russian contacts in a Mayfair hotel bar.
Andrei Lugovoi and Dmitri Kovtun are wanted for the 44-year-old's murder but remain in Russia, where they deny any involvement in his death.
They are believed to have been some of his Russian contacts for his work for British intelligence agencies and other private investigation firms in the UK.
Mr Attew said that although he never spoke to the murdered spy about his personal safety, in their line of work this was not something they were "flippant about".
"Even in the commercial arena, we are all very sensitive about our own safety," he said.
The inquiry heard the first report Mr Attew asked Mr Litvinenko to prepare was on former KGB officer and current Director of The Federal Narcotics Service of Russia, Viktor Ivanov.
Mr Attew revealed that a second report had to be prepared, after the initial one - for which Andrei Lugovoi was the source - was inadequate and amounted to only one third of a page.
The second report was "exceptional" according to Mr Attew, and contained details about Ivanov's career, personal life and criminal activity.
Written by former KGB worker Yuri Shvets, the report said Ivanov had "Putin's ear", which meant he could implement his own business interests.
It alleged that Ivanov was linked to a drug smuggling criminal enterprise.
The report read: "Ironically, while Ivanov was co-operation from with the gangsters, he was promoted to operational department to fight against smuggling.
"When Ivanov was co-operating with gangsters, he was protected by Vladimir Putin who was responsible for foreign economic relations...Putin himself was not Mr Clean at that time."
Referring to the first report, Mr Attew told the inquiry that it would not have looked any different if it had been prepared to "shield" Ivanov.
Before Mr Attew knew Lugovoi had prepared the first report, Mr Litvinenko introduced the two of them at an airport meeting, the inquiry heard.
He had described Lugovoi as a "good friend" who could be helpful to the business in the future.
But Mr Attew did not take to the contact. He said: "Seven years watching people around gaming tables, and reading body language, left me feeling extremely uncomfortable."
He conceded that he took an immediate dislike to the former Russian intelligence agent and did not want him in the London offices.
Mr Attew described Lugovoi as being "scary" and "cold".
However, he added that Mr Litvinenko made no mention of him from his hospital bed in November 2006.
Mr Attew explained that when he discovered Mr Litvinenko had been given the radioactive agent, he linked it to a break-in at Titon's Grosvenor Street offices in June 2006.
He said that nothing was taken, and he and a colleague removed every socket and ceiling tile, but did not find anything, leaving him to believe the break in had been a "recce".
"I didn't doubt that they were linked," he added.
The inquiry then heard how Lugovoi had allegedly been stopped at a Moscow airport in September 2006, with the Ivanov report that Shvets had prepared.
Mr Attew said that after the spy's poisoning, he received phonecalls from Shvets, in which he learned that he was the author of the second - more comprehensive - report on Ivanov, and that his own name had been brought up in Russia as having a "particular relationship" with Mr Litvinenko.
Asked by Ben Emmerson QC, for Marina Litvinenko, what they thought this relationship was, Mr Attew replied: "That I was Sasha's handler for MI6."
He then conceded that he felt he had a responsibility to assist in Mr Litvinenko establishing himself commercially.
The inquiry heard evidence that traces of polonium-210 were found in an office Lugovoi and Kovtun visited on October 31 2006.
The offices of Eco3 were opposite the building Mr Litvinenko regularly visited as part of his work for Titon. Nikolay Gorokhov, who had just started working at the investment company, told the hearing he remembered the two men attending a meeting at the address in Grosvenor Street, central London.
He said that the following day, Lugovoi returned to the office, this time casually dressed. "I spoke to him for about 15 to 20 minutes and the subject was a football match."
Asked to describe the Russian's demeanour, Mr Gorokhov added: "I would say the second time when I had the chance to see him more, he was more relaxed. And he told me that his wife was in London and she was doing shopping while he was here.
"I can't say that anything at all struck me, he was very calm and relaxed."
Mr Gorokhov told the inquiry that on November 23 - the day of Mr Litvinenko's death - police arrived to check the office for radiation and that traces of polonium-210 were found.
He added that he was also tested and in December that year was told that he had tested positive for the radioactive agent.
The inquiry also heard from Detective Inspector Craig Mascall, who explained that in October 2006 Lugovoi and Kovtun visited London on a number of times. On October 31 they travelled as part of a large group, claiming to be in the capital for Arsenal's match against CSKA Moscow.
Mr Mascall said hotels where members of the group had been staying and their plane seats had been tested and found positive for the substance. Lugovoi's seat was found to have highest reading.
The inquiry resumes at the Royal Courts of Justice tomorrow.