Opposition leader Boris Nemtsov told the Associated Press on Tuesday that police had said the report was being investigated for extremist content.The 48-page document charges Putin with corruption during his 10 years in power. After two four-year terms as president, Putin has retained authority as premier.Nemtsov says the confiscation occurred at a printing house in the Western city of Smolensk. Its police chief, Yury Sterlikov, said he had inquired about the report but denied impounding it.Last week police seized thousands of copies in St. Petersburg.