Hamburg - Police found evidence in two homes in Germany of past radioactivity, as they followed Saturday the trail of a man linked to the poisoning death of Russian dissident Alexander Litvinenko.
Police had arrived late Friday at an apartment in Hamburg belonging to businessman Dmitry Kovtun, one of a pair of Russians who met with Litvinenko in London on the day that authorities believe he was poisoned with polonium 210.
Police said Kovtun's own apartment was not contaminated with polonium, but another apartment belonging to his 31-year-old German ex-wife in the same building showed signs that something radioactive had been there in the past.
As the inquiry widened, detectives searched the home of Kovtun's former mother-in-law, a lawyer, in Haselau, a village 25 kilometres to the west in the adjacent state of Schleswig Holstein.
Police spokesman Andreas Schoepflin said there were telltale signs that something radioactive had been there as well.
It was not clear from the police statements if anything radioactive was still at the two sites. Police appealed to anybody who had been in contact with Kovtun and the two women to provide urine samples.
The clues were found at two locations in the ex-wife's apartment.
Asked if the poison plot against Litvinenko had been mounted from Hamburg, police said there was no evidence of this whatsoever.
An ad-hoc federal German police unit, code-named 'The Third Man,' was established to pursue the inquiry.
Kovtun is in serious condition in a Moscow hospital with suspected radiation poisoning.
Painstaking measurements were continuing Saturday because the alpha particles emitted by radioactive polonium travel less than 1 millimetre before vanishing. The substance is thus toxic when ingested, but is not dangerous while being carried in a container.
After an evacuation, residents were allowed in the night to return to the building in the Hamburg district Ottensen, a trendy and densely populated neighbourhood. Experts said there was no danger.
Polonium 210 is a toxic isotope that was ruled to have caused Litvinenko's death on November 23. Evidence gathered by British authorities suggests that he was exposed on November 1 at London's Millennium Hotel, just after Kovtun had arrived from Hamburg.
Litvinenko and Kovtun were both former Russian intelligence agents.
© 2006 dpa - Deutsche Presse-Agentur
Polonium 210, a radioactive substance that killed ex-spy Alexander Litvinenko, has been found inside two buildings located in Hamburg, Germany.

The radiation was found in the home of Dmitry Kovtun's ex-wife. Litvinenko and Kovtun met together at a London, England pub on November 1, 2006. Kovtun is now being treated at a hospital in Germany for radiation exposure, but his condition is not known. No radiation was found at Kovtun's apartment.

The second location in Germany to test positive for radiation is an apartment belonging to the ex-mother in law of Kovtun. Her home is located in Pinneberg, Germany.