Polish prosecutors say that the U.S. is hampering their investigation into the secret CIA prison by snubbing requests for vital documents, including the Senate report detailing CIA practices.

Published in December, the report was redacted and did not mention Poland, but other facts in it pointed to the country and a prison there from 2002-2003.

Spokesman for Polish prosecutors, Piotr Kosmaty, said Saturday that Poland immediately asked the U.S. for a full version of the document, but has had no response.

"This is undoubtedly hampering the investigation," Kosmaty told The Associated Press.

One former Polish official has been charged in the investigation, underway since 2008.

The U.S. report prompted Polish leaders of the time to admit — after years of denials — that they authorized a prison, but not torture.