POLITICO obtained the memo from Blaine, Wash., immigration attorney Len Saunders, who received it from an anonymous source. The Peace Arch border crossing in Blaine became the subject of a nationwide uproar earlier this month as dozens of Iranian Americans reported being held for questioning there about their family and military ties to Iran.

A CBP spokesperson declined to comment on “leaked documents” and did not respond to specific questions about the document's authenticity. The agency has previously denied issuing any directive related to "detaining Iranian-Americans and refusing their entry into the U.S. because of their country of origin."

Rep. Pramila Jayapal (D-Wash. said in a statement the document “matches exactly” the vetting process CBP leadership described to her and her staff during a briefing last week.

While she said her office is working to verify the memo, “it is becoming increasingly clear from multiple conversations with travelers and CBP staff that there was, indeed, a directive from the Seattle Field Office to target Iranian Americans for secondary screening solely based on their country of origin and despite the fact that they were largely American citizens, legal permanent residents and legal visa holders.”

The memo also outlines "secondary procedures" if an individual meets "high side vetting criteria," such as criminal or Iranian military ties. "Even if they are not of SHIA faith, anyone can state they are Baha'i, please question further to determine this is the case," it reads. "When in doubt send for high side checks."

The document says officials were looking for anyone who's been a member of Iran's elite paramilitary force, known as the Quds Force.

Saunders previously disclosed to POLITICO that a CBP officer who works for the Seattle field office alleges officials there directed frontline officers to detain and question Iranian-born travelers at ports of entry across the sector, which spans from Washington state to Minnesota.

Jayapal told POLITICO this week that her office heard from another CBP source since that allegation surfaced. "The story is very corroborated," she said.

The document’s existence was first reported by The Northern Light, Blaine’s newspaper.