WASHINGTON  In February, a Department of Homeland Security intelligence official wrote a “threat assessment” for the police in Wisconsin about a demonstration involving local pro- and anti-abortion rights groups.

That report soon drew internal criticism because the groups “posed no threat to homeland security,” according to a department memorandum released on Wednesday in connection with a Freedom of Information Act lawsuit. The agency destroyed all its copies of the report and gave the author remedial training.

That was just one of several cases in the last several years in which the department’s intelligence office improperly collected information about American citizens or lawful United States residents, the documents show.

In March 2008, the office produced a “terrorism watch list” report about a Muslim conference in Georgia at which several Americans were scheduled to speak, even though it “did not have any evidence the conference or the speakers promoted radical extremism or terrorist activity,” and such speech is constitutionally protected, an internal report said.