Looks like the FBI was very interested in What Cohen has to say.
“Former U.S. Attorney Chuck Rosenberg, now an NBC News analyst, says there's a high bar for having a wiretap approved.
"The affidavits are typically highly detailed and carefully vetted by experienced lawyers," he said. "In all cases the wiretap must be approved by a federal judge."
Rosenberg said that wiretaps are usually approved for an investigation into a current crime and not solely for possible crimes that have been committed in the past.
"This is an exacting process where the government must demonstrate to a federal judge that there is an ongoing crime."
According to sources close to Giuliani, Trump was told by Cohen not to call him because he was afraid that his lines had been tapped, this shortly after the raid on Cohen’s home, storage, offices, and hotel.