The US Senate Judiciary Committee on Thursday authorized Congress to issue subpoenas to those who participated in an FBI investigation into President Donald Trump.

The investigation, codenamed Crossfire Hurricane, was conducted under the Obama administration during the 2016 election and investigated the Trump campaign’s alleged collusion with Russia. The goal of the subpoenas is to assess the original validity of opening the investigation.

The subpoenas are for “documents and communications referenced in, and testimony at a hearing or deposition of any individual named or identified by pseudonym in, the report titled ‘Review of Four FISA Applications and Other Aspects of the FBI’s Crossfire Hurricane Investigation’ issued by the U.S. Department of Justice Inspector General.”

The committee also authorized subpoenas for “documents and communications related to, and the testimony at a hearing or deposition of any current or former executive branch official or employee involved in, the Crossfire Hurricane investigation,” and documents related to these hearings or investigations between individuals such as former US Attorney General Loretta Lynch, former FBI director James Comey, and former National Security Advisor Susan Rice.

The Judiciary Committee was divided in its decision to authorize the subpoenas. Some members argued against the decision citing fears that it would merely reopen an investigation that was conducted exhaustively over 19 months and already submitted a lengthy report on its findings and reasoning.