Senate Judiciary Committee leaders have sent letters to former Attorney General Loretta Lynch and others asking for information about allegations of political interference in the FBI's investigation into former Secretary of State Hillary Clinton's use of a private email server.

The letters from Chairman Chuck Grassley, R-Iowa, Ranking Member Dianne Feinstein, D-Calif., Crime and Terrorism Subcommittee Chairman Lindsey Graham, R-S.C., and Ranking Member Sheldon Whitehouse, D-R.I., come as the panel carries on its broad investigation into last month's abrupt firing of FBI Director James Comey.

In addition to Lynch, the four senators sent letters to Leonard Benardo of the Open Society Foundations and the group's general counsel Gail Scovell, as well as Clinton campaign staffer Amanda Renteria.

The New York Times reported in April that the FBI obtained hacked documents, including one written by a "Democratic operative who expressed confidence that Ms. Lynch would keep the Clinton investigation from going too far."

The Washington Post reported a similar story in May, including more details about the communications and an email, considered dubious, from then-Democratic National Committee Chairwoman Debbie Wasserman Schultz to Benardo that indicated Lynch had privately assured Renteria that the FBI's investigation wouldn't "go too far."

Comey was allegedly concerned such communication would call into question the FBI's independence, and decided to announce the conclusion of the email investigation. This decision has been cited, in part, by Trump as reason for his firing.

"The reports come amidst numerous allegations of political inference in controversial and high-profile investigations spanning the current and previous administrations. The Senate Judiciary Committee has jurisdiction over the FBI and Justice Department and is obliged to oversee any potential misconduct or inappropriate political influence at these agencies," the senators said Friday.