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Update 5:24 p.m. ET: NBC News reporter Julia Ainsley clarified that Michael Cohen's phone calls were being monitored but not listened to. NBC News had originally reported that Cohen's phone lines had been wiretapped — which would allow federal investigators to hear the content of his calls — but Ainsley said that Cohen's phones were merely being subject to a pen register, which would allow agents to determine with whom Cohen was communicating but not what was being said. Our original story appears below.

President Trump's personal lawyer, Michael Cohen, was reportedly wiretapped by federal investigators in the weeks leading up to the raids on his home and office in early April, two people familiar with the legal proceedings told NBC News. After the raids, Trump's legal team reportedly advised the president against contacting Cohen on the suspicion that the lawyer's phone conversations were being recorded by prosecutors.

Trump, who doesn't exactly have a reputation for following his lawyers' advice, apparently placed a call to Cohen in the days after the raid anyway. Rudy Giuliani, who has since joined Trump's legal team, reportedly had to specifically instruct Trump not to call Cohen again after he learned about the president's call, people familiar with the exchange told NBC.

Cohen is expected to be under federal investigation for possible bank fraud, wire fraud, and campaign finance violations. On Thursday, Trump confirmed that Cohen had paid $130,000 to adult film star Stormy Daniels to keep quiet about her allegations of an affair with Trump, although the president stressed that the payment was from his personal funds, rather than from the campaign's coffers.

In order to have obtained a wiretap on Cohen, investigators would have had to have convincingly demonstrated that there is a possibility of an ongoing crime. "The affidavits are typically highly detailed and carefully vetted by experienced lawyers," said former U.S. Attorney Chuck Rosenberg. "In all cases the wiretap must be approved by a federal judge."

At least one phone call between a line linked to Cohen and the White House was reportedly intercepted. Read more about the phone tap at NBC News.