The FBI is investigating an assassination threat against Rep. Ilhan Omar — written in Sharpie on a gas station bathroom stall in her district.

The investigation was sparked by a message scrawled on a stall in the men’s room at a Holiday gas station in Rogers, Minnesota. It read, “Assassinate Ilhan Omar,” according to an Instagram post last month from 45-year-old Brian Raines.

Omar, a freshman Minnesota Democrat and one of the first Muslim women elected to Congress, tweeted about the graffiti Friday. She blamed Republicans for linking her to Muslim terrorist acts like 9/11.

“No wonder why I am on the ‘Hitlist’ of a domestic terrorist and ‘Assassinate Ilhan Omar’ is written on my local gas stations,” the congresswoman tweeted.

Her tweet linked to an article from NBC News about a poster in the West Virginia statehouse that suggests Omar winning a congressional seat is “proof” Americans have “forgotten” about the 9/11 terrorist attacks.

“Look no further, the GOP’s anti-Muslim display likening me to a terrorist rocks in state capitols and no one is condemning them!” Omar added in her tweet.

The FBI is in the “initial stages” of an investigation and looking into the matter with local law enforcement, an FBI spokesman in Minnesota told twincities.com.

“We are aware of that piece of graffiti at the convenience store and are looking into it with some of our law enforcement partners,” spokesman Kevin Smith told the publication.

In a little over two months on the job in Washington, Omar has found herself in series of controversies involving religious stereotypes, some stemming from her own comments on the U.S.-Israel relationship.

Democrats and Republicans alike have accused her of using insensitive and anti-Semitic language when questioning the status-quo of the U.S.’ political and military relationship with Israel.

“I want to talk about the political influence in this country that says it is okay to push for allegiance to a foreign country,” Omar said over the weekend, referring to politicians and special interest groups trying to pressure her and others to support Israel.

Scores of lawmakers condemned Omar for the comments, saying that it plays on an anti-Semitic trope that Jewish people are not capable of loyalty to America because they have dual loyalty to Israel. The House plans to take up a resolution, intended to rebuke Omar without directly naming her and condemn such language.