WASHINGTON — Senate Judiciary Committee members of both parties praised the Justice Department’s inspector general, Michael E. Horowitz, during a hearing on Wednesday for unearthing a litany of serious problems with one aspect of the Russia investigation: the F.B.I.’s pursuit of a court order to wiretap a former Trump foreign policy adviser, Carter Page.

At a hearing to discuss his new long-awaited report, Mr. Horowitz underscored longstanding serious issues with how the F.B.I. wields its surveillance tools, and he portrayed the bureau during the time of the Russia investigation as dysfunctional. Though he said he found no evidence the mistakes were the result of political bias, as President Trump and his allies have long claimed, he cautioned that no one should view his report as a vindication of officials involved in the investigation. “The activities we found here don’t vindicate anybody who touched this,” he said.

The hearing highlighted problems with F.B.I. surveillance.

Many of the problems that Mr. Horowitz uncovered centered on investigators’ use of a dossier of opposition research about Mr. Trump compiled by a British former spy, Christopher Steele, as part of the materials submitted to the court to show they had probable cause to suspect that Mr. Page was an agent of a foreign power.

Senator Lindsey Graham of South Carolina, the Republican chairman of the Judiciary Committee and a close ally of President Trump, slammed the F.B.I. for using the dossier in the Page wiretap applications — and for continuing to use it to seek renewals even after they interviewed Mr. Steele’s primary source and he contradicted what the dossier said.