Federal prosecutors worried that Rudy Giuliani would destroy evidence or intimidate witnesses if he knew he was under investigation

• Prosecutors were worried that Rudy Giuliani would destroy evidence or tamper with witnesses if he knew he was under investigation.
• Giuliani's lawyer made the disclosure in a letter to the federal judge overseeing his case.
• The feds are investigating whether Giuliani broke foreign lobbying laws.

A defense lawyer representing former New York City mayor Rudy Giuliani revealed on Monday that prosecutors were worried that Giuliani would destroy evidence or intimidate witnesses if he knew he was under a federal criminal investigation.

In a letter to US District Judge Paul Oetken, who is overseeing the Giuliani case in the Southern District of New York, Giuliani's lawyer Robert Costello wrote that federal prosecutors were concerned that "if Giuliani were informed of the existence of the warrant, he might destroy evidence or intimidate witnesses."

Costello was referring to a November 2019 search warrant that prosecutors secured to scour Giuliani's iCloud as part of an ongoing investigation into whether he violated foreign lobbying laws.

According to his letter, prosecutors wrote that "there is reason to believe that notification of the existence of this warrant will result in destruction of or tampering with evidence, and/or tamping (sic) with potential witnesses, or otherwise will seriously jeopardize an ongoing investigation."

The inquiry into Giuliani entered an aggressive new phase last month, when the feds raided his apartment, office, the home of his Washington, DC, associate Victoria Toensing, and seized several electronic devices belonging to Giuliani and his personal assistant, Jo Ann Zafonte.

Costello in his letter raised "serious concern over the broad and sweeping nature of the searches executed on an attorney's home and law office, and the covert search and review of the same attorney's iCloud account in 2019," and the government's decision not to inform Giuliani about the search until a year and a half later.

He went on to say that the allegation that Giuliani would tamper with witnesses or evidence "strains credulity."

"It is not only false, but extremely damaging to Giuliani's representation," he wrote in the letter, which is Giuliani's first formal response to the FBI's raids. "It is not supported by any credible facts and is contradicted by Giuliani's efforts to provide information to the Government."

He continued: "We should be allowed to question the Government as to what basis it had, if any, to make that assertion. Accordingly, we request the information that was presented in the iCloud warrant to justify the NonNotification Order" as well as access to "the application for any extension of the non-disclosure provision which originally lasted for a year."

The purpose of Costello's letter was to respond to the government's request for the appointment of a "special master" to review documents and electronic records that were seized in the FBI's raids. A special master is an outside legal scholar - typically a former judge - who goes through these materials to filter out potentially privileged information when the target of a raid is a practicing lawyer, like Giuliani.

At the time that the feds obtained the warrant to search Giuliani's iCloud, he and then President Donald Trump were at the center of a political firestorm after it surfaced that they tried to strongarm the Ukrainian government into launching bogus investigations targeting the Bidens ahead of the 2020 election. Those efforts, which Giuliani spearheaded on Trump's behalf and at his direction, resulted in Trump's first impeachment.

They also make up the central thread of the longrunning federal investigation into Giuliani. Specifically, prosecutors are examining whether Giuliani's campaign to obtain dirt on the Bidens was carried out solely in his capacity as Trump's lawyer, or if he was also working on behalf of foreign interests who believed they would benefit from Trump's reelection.

If Giuliani was working on behalf of foreign interests, it could violate a law known as the Foreign Agents Registration Act (FARA).

FARA requires that American citizens notify the Justice Department of any contacts they have with foreign governments or officials, and if they interact with the US government or media at the direction of those officials.

Giuliani has denied any wrongdoing and he has not been charged with a crime. Costello called the FBI's raids last month "legal thuggery" and said in a statement that they reflected a "corrupt double standard" at the Justice Department.

Trump, for his part, released an initial statement defending Giuliani following the FBI's raids and called him a "great patriot." But in the days since, he's largely blown off pleas for assistance from those close to his former lawyer and longtime attack dog.

"It's a question now of whether or not [the former president and his team] want to leave Rudy to fend for himself or if they're going to take a stand against this," one person close to Giuliani told The Daily Beast. "Right now, we don't know."