The top Republican on the Senate Judiciary Committee wants the FBI to turn over information related to its alleged offer to hire the author of an unverified and damaging dossier about President Trump.

Judiciary Committee Chairman Charles Grassley, R-Iowa, sent a letter Monday to FBI Direct James Comey, asking first if the FBI ever attempted to hire Christopher Steele. He is a former British spy who assembled a dossier on Trump that accused the president during a past trip to Russia of hiring hookers to perform lewd acts, among other claims.

Grassley said in the letter to Comey that Steele had at one point been paid by Democrats to dig up dirt on Trump.

"The idea that the FBI and associates of the Clinton campaign would pay Mr. Steele to investigate the Republican nominee for president in the run-up to the election raises substantial questions about the FBI's independence from politics, as well as the Obama administration's use of law enforcement and intelligence agencies for political ends," Grassley said in the letter to Comey.

Grassley said he is seeking from the FBI "records related to the reported agreement" as well as answers to a list of questions, including who decided to hire Steele and whether the dossier was used to seek other warrants.