SAN FRANCISCO — Lawmakers are investigating the Twitter account that first shared a video of a group of white teenagers taunting a Native American protester in Washington, a collision of racial groups and politics that went viral.

The House Intelligence Committee asked Twitter on Tuesday to provide information about how the video took off so fast. The committee said it was also awaiting information about the account that first uploaded the video and accounts that helped spread it by retweeting it.

Senator Mark Warner, a Democrat from Virginia, separately asked Twitter to provide more information about the video. A spokeswoman for Mr. Warner said Twitter had found that the account originated in the United States.

Twitter declined to comment on the video, on the requests from the Intelligence Committee and Mr. Warner, and on whether the account was domestic.