Washington (CNN) The White House has a list of 12 people whom they believe could have anonymously penned the explosive New York Times op-ed, an outside adviser told the newspaper Thursday night.
The op-ed, written by a senior Trump administration official, bashed the President as amoral and claimed there is a "resistance" within the administration. The essay has enraged Trump and touched off a furious search inside the administration for its author.
Republican Sen. Rand Paul of Kentucky told reporters Thursday that he thinks any White House employee with a security clearance should undergo a lie detector test to determine who wrote it.
Advisers to President Donald Trump entertained the idea, briefly discussing it among themselves, according to the Times.
The newspaper also reported that people close to Trump floated another option -- forcing senior officials to sign sworn affidavits that could be used in court if necessary.
A day after the op-ed was published, the highest-ranking officials in the Trump administration, including Vice President Mike Pence, took the extraordinary step of publicly denying they or their offices were behind the essay.
The Times reported that several White House officials still eyed Pence's staff as the source of the op-ed.
The White House has been on the hunt for the author of the op-ed as well as the sources for a forthcoming book by journalist Bob Woodward, CNN has reported.
Aides are following leads based on the way the op-ed is written, looking at key words used in the editorial that stand out, a source close to the White House told CNN.