whistleblower illo 01
Washington CNN  — 

The legal team representing the whistleblower who ignited the impeachment investigation has received death threats that have led to at least one law enforcement investigation, according to a source familiar with the situation.

The FBI deemed the threat not to be credible after meeting with the individual who sent it, the source said.

“There have been a myriad of disturbing emails and voicemails sent to the legal team, with a few select messages crossing the line enough into direct threats of harm that have resulted in follow up from relevant law enforcement entities,” according to the source.

The Wall Street Journal first reported that the threats had led to at least one law enforcement probe.

Trump has repeatedly derided the anonymous whistleblower whose complaint alleges the President abused his official powers in a July phone call with Ukrainian President Volodymyr Zelensky “to solicit interference” in the 2020 election.

Trump, who has denied any wrongdoing, said last month that whoever had provided the whistleblower with information about his call with Zelensky is “close to a spy,” adding that in the old days spies were dealt with differently. The comments prompted lawyers for the whistleblower to send a letter to acting Director of National Intelligence Joseph Maguire outlining “serious” safety concerns for their client as Trump continues to take aim at the whistleblower.

“The purpose of this letter is to formally notify you of serious concerns we have regarding our client’s personal safety,” the letter says, adding that recent comments by Trump are reason for “heightened” concern.

“The events of the past week have heightened our concerns that our client’s identity will be disclosed publicly and that, as a result, our client will be put in harm’s way.”

Mark Zaid, one of the lawyers representing the whistleblower, told CNN earlier this month that he’s received “nasty voicemails and lots of nasty emails” since he started representing the whistleblower, but that it’s “the same type of crap we’ve been receiving for years, but in greater number.”

As Democratic lawmakers conduct a steady stream of closed-door depositions as part of the impeachment inquiry, Zaid, along with Andrew Bakaj, who is also on the whistleblower’s legal team, have argued there is no need for their client to testify in person.

Last week, the lawyers released an October 8 letter to leaders of the Senate Intelligence Committee in which they say an in-person meeting with committee staff is a “non-starter,” citing the need to guard the whistleblower’s safety.

CNN’s Oliver Darcy, Manu Raju and Jeremy Herb contributed to this report.