"A full investigation by law enforcement officials will ensure that the crucial facts and witnesses in this matter are assessed in a nonpartisan manner and that the committee is fully informed before conducting any hearing or making any decisions", the letter states.
"I have never done anything like what the accuser describes - to her or to anyone", Kavanaugh said on Monday.
Lisa Banks, a Ford attorney, wrote that Grassley's plan to call just two witnesses, Kavanaugh and Ford, "is not a fair or good faith investigation" and said "multiple witnesses" she did not name should be included.
"Dr. Ford was reluctantly thrust into the public spotlight only two days ago", Ford's attorney said in a statement Wednesday.
"The rush to a hearing is unnecessary, and contrary to the Committee discovering the truth", Banks wrote.
Why did the Senate set a deadline?
Kavanaugh has agreed to testify in front of the Senate Judiciary Committee on Monday, but Blasey has yet to commit to testify.
A group of about 40 protesters, majority women, clogged the lobby of Grassley's Senate office on Thursday.
According to the spokesperson, the Federal Bureau of Investigation "does not make any judgment about the credibility or significance of any allegation".
"I have scheduled the hearing continuation for this Monday because Dr. Ford, through her counsel, expressed the desire to tell her story under oath".
Grassley said the committee offered Ford "the opportunity to share her story" in a public or a private hearing, or staff interviews, "whichever makes her most comfortable".
What is the allegation against the judge?
Sen. Claire McCaskill says she will vote against Brett Kavanaugh's nomination to the Supreme Court, but the Missouri Democrat, who is facing re-election in November, says it is not because of allegations of sexual misconduct swirling around the nominee.
President Trump's son (left) disseminated an image of a make-believe note from a young boy to a young girl, asking her to be his girlfriend, and attributing it to Kavanaugh; at the time Sen.
No matter what happens, the incident has turned a nomination that Republicans once thought was a winning issue for their party in the midterms into a major quagmire.
Kavanaugh has denied the allegations against him.
Democrats are casting Republicans as strong-arming a wronged woman, their eyes on a #MeToo movement that has caught fire and exploded the careers of dozens of male titans. "Very hard for me to imagine that anything happened", Trump said.
Hillary Clinton says the White House should request an FBI investigation of the sexual-assault accusation facing Supreme Court nominee Brett Kavanaugh and any refusal to do so by Republicans amounts to rushing to confirm him.
Ford has said she wants the FBI to investigate her accusation before she would testify.
Fellow Republican Susan Collins of ME said on Wednesday that she hopes Prof Ford "will reconsider and testify" on Monday.
Thomas and Kavanaugh have denied the accusations against them.
Both have called on Judge Kavanaugh and Prof Ford to testify under oath.