Washington, D.C. – Federal investigators have been reportedly monitoring the phone logs of Michael Cohen, President Trump’s personal attorney, according to NBC News.

NBC News on Thursday initially claimed that the FBI investigation of Cohen included wiretapping of his phones lines, but following statements from US officials disputing the claim, NBC issued a correction clarifying that Cohen’s calls had actually been logged through the use of what is known as a “pen register.”

The monitoring has reportedly been ongoing for an unknown amount of time, but included the weeks preceding the raid on Cohen’s hotel room, office and home.

The NBC News report went on to state that at least one call between Cohen and someone at the White House, possibly Trump or an intermediary, was logged by prosecutors:

The calls are logged by what is commonly referred to as a pen register, which records the number of the phone that made the call and the number that received it, but does not record the contents of any conversation.

NBC News originally reported that Cohen’s phone lines had been wiretapped, meaning a judge had given investigators approval to listen to phone calls. Three senior U.S. officials now dispute that, saying the monitoring of the calls was limited to a log of calls.

At least one phone call between a phone line associated with Cohen and the White House was logged, the person said.

Previously, federal prosecutors in New York have said in court filings that they have conducted covert searches on multiple e-mail accounts maintained by Cohen.

Following the raid on Cohen, Trump’s legal team reportedly advised him to not speak with Cohen – advice Trump is not believed to have followed. After new lead attorney Rudy Giuliani came aboard the president’s legal team and became aware of Trump’s call to Cohen he instructed him to not call Cohen out of caution that prosecutors were surveilling the communications.

In addition, sources close to Giuliani, said the former mayor of New York City and ex-federal prosecutor, reportedly told Trump that he believes that Cohen is likely to flip and become a prosecutorial witness. Trump has repeatedly stated on numerous occasions that he believes Cohen — who has represented Trump and the Trump Organization for decades prior to Trump becoming president — will not cave to pressure to cut a deal to turn on him.

NBC News reported:

It is unclear what incriminating information Cohen could give prosecutors on Trump, if he chose to cooperate. He represented Trump and the Trump Organization in its business dealings for nearly two decades before Trump became president. Special counsel Robert Mueller is interested in any information that federal investigators in New York may pick up that would be relevant to his investigation into possible collusion between the Trump campaign and Russia.

Cohen has previously said publicly that he would invoke his Fifth Amendment rights if subpoenaed to avoid incriminating himself before a grand jury and there is no indication from public filings that Cohen is cooperating in the probe.