The FBI has asked to interview the Central Intelligence Agency whistleblower whose complaint touched off the Ukraine impeachment investigation, a source directly familiar with the matter told NBC News.
An agent from the FBI's Washington field office reached out to the whistleblower's lawyers last month to seek an interview about the substance of the complaint.
Zaid has claimed that the whistleblower and his legal representation has been threatened, but Yahoo's sources said the agent who wants to question the whistleblower did not refer to the threats, even though they've been reported to the Federal Bureau of Investigation.
The FBI did not immediately respond to a request for comment. The FBI received a referral from the intelligence watchdog about the contents of the complaint, according to US media reports. They included investigations into former Vice President Joe Biden and a debunked theory about Ukrainians meddling in the 2016 election.
The Justice Department determined in September, after reviewing the whistleblower's complaint, that it saw insufficient evidence to undertake a criminal investigation into Trump for possible campaign finance violations.
Taylor Swift allowed to perform old songs at AMAs
But shortly thereafter, the producers distanced themselves from the situation, saying it was between Swift and her ex-label. Even so, rumor has it, if Swift does go through with her show, the presentation will be unforgettable.
The whistleblower's complaint was submitted to the Inspector General in early August.
Republicans, including Trump, have made repeated calls for the whistleblower to reveal himself and testify as a material witness in the impeachment hearings. Andrew Bakaj, the lead attorney for the whistleblower, also declined to comment but said that it remained critical for the identity of his client to be protected for his safety.
The Wall Street Journal says lawyers representing the officer and the firms they work for have received multiple death threats since the whistleblower became a cause celebre.
The lawyers have offered to make their client available to answer congressional investigators' written questions under oath, but lawmakers have yet to accept that offer.
Democrats have said such charges are misleading and emphasized that the concerns raised in the whistleblower's complaint have been largely confirmed by other witness testimony in the impeachment inquiry.