Sens. Chuck Grassley, R-Iowa, and Lindsey Graham, R-S.C., are calling on former national security adviser Susan Rice to explain an email she wrote to herself on the day of Donald Trump’s inauguration that insisted Obama wanted to make sure the probe into Russia's election meddling was done "by the book."

On Jan. 20, 2017 — moments before Trump took the oath of office to become president — Rice emailed herself about a briefing that took place that month with the intelligence community about Russian hacking during the 2016 presidential election.

Then-President Barack Obama had a meeting on Jan. 5, 2017 with then-FBI Director James Comey and then-Deputy Attorney General Sally Yates. Rice and then-Vice President Joe Biden were also present at the Oval Office meeting.

At the end of her email describing the meeting, Rice wrote that from a national security perspective, Obama “said he wants to be sure that, as we engage with the incoming team, we are mindful to ascertain if there is any reason that we cannot share information fully as it relates to Russia.”

The email, Grassley and Graham say, is “unusual” and want answers on a variety of questions.

In a letter sent to Rice last week, the senators asked her to further explain why she sent the email and if it pertains to her involvement in the Trump-Russia dossier.

Grassley and Graham asked her to tell them when she first became aware of the FBI’s investigation into allegations of collusion between the Trump campaign. The FBI reportedly began investigating links between Trump and Russia sometime in July 2016.

They also asked whether Comey and Yates discussed the dossier at the Oval Office meeting with Obama and how Comey described the FBI’s relationship with the dossier's author, Christopher Steele.

“Did President Obama have any other meetings with Mr. Comey, Ms. Yates, or other government officials about the FBI' s investigation of allegations of collusion between Trump associates and Russia?” the letter asked. It asked Rice to reply by Feb. 22.

Grassley is chairman of the Senate Judiciary Committee, on which Graham also sits. In a Monday statement accompanying the letter to Rice, Grassley and Graham said this is part of their “continued efforts to conduct oversight” of the Department of Justice and FBI.