An investigation of the U.S. Interior Department found serious flaws related to 15 decisions on policies for species at risk of becoming extinct, said the report delivered to Congress by Inspector General Earl E. Devaney.

One of those decisions involved reducing the number of waterways considered critical habitat for the endangered bull trout, The New York Times reported Tuesday.

The report describes "something akin to a secret society residing within the Interior Department that was colluding to undermine the protection of endangered wildlife and covering for one another's misdeeds," said Rep. Nick J. Rahall II, D-W.V., who leads the House Natural Resources Committee.

The report suggests some of the policy decisions may need to be re-examined under the administration of President-elect Barack Obama.

Interior officials said they had yet to read the report and could not comment, the Times reported.