A top aide to Senator Charles Grassley was attacked outside her home a week ago, and Grassley has asked the F.B.I. to investigate. The F.B.I. and U.S. Capitol Police are investigating amid concerns the incident may be connected to Emilia DiSanto’s work for Grassley. DiSanto is chief investigator for the Senate Finance Committee, which Grassley chairs.

Last Wednesday, she was attacked outside her home in a D.C. suburb by a white man wielding what she thinks was a baseball bat. Authorities say she received significant injuries, including a head wound. She is back at work this week.

Grassley spokeswoman Jill Kozeny told Radio Iowa via e-mail that “all of Senator Grassley’s staff members have been informed of what is known and not known about the attack and advised to be cautious until the matter is resolved.” Kozeny went on to say that Grassley has “taken steps to ensure the staff feels as safe as possible.” But she didn’t say what those steps were.

Kozeny said there’s “no evidence” at this point to rule out that the assault was “work-related” but there’s also no evidence at this point to suggest it is. Grassley has a long record of challenging powerful authority figures and institutions, ranging from the F.B.I. and the Defense Department to the pharmaceutical industry.