Former New York City Mayor Rudy Giuliani, personal attorney to U.S. President Donald Trump, speaks about the 2020 U.S. presidential election results during a news conference in Washington, November 19, 2020.Jonathan Ernst | ReutersLawyers for Rudy Giuliani cited communications he would have had with then-President Donald Trump in a letter to a judge attacking the legitimacy of a 2019 federal search warrant for an iCloud account belonging to the former New York City mayor.That search, which until recently was unknown to Giuliani, came two years before the search in late April of his Manhattan apartment and office as part of an ongoing federal criminal probe related to Giuliani’s dealings in Ukraine.In 2019, Giuliani and other allies of Trump had sought damaging information on now-President Joe Biden and his son Hunter Biden, whose business dealings in Ukraine had come under scrutiny.Those efforts to dig up dirt on the Bidens became a central component of Trump’s first impeachment proceeding. Trump was impeached in the House and acquitted in the Senate.Giuliani’s lawyers argue that there are serious questions about the legitimacy of the iCloud warrant and the propriety of federal prosecutors reviewing material seized from that account because of the risk of violating attorney-client privilege attached to both Giuliani and Trump.Giuliani has served as Trump’s personal lawyer.”In this case, federal prosecutors have taken the unprecedented step of covertly seizing data and files of the personal attorney to the former President of the United States,” wrote the lawyers, Robert Costello and Arthur Aidala, to Manhattan federal court Judge J. Paul Oetken in their letter sent last week.”Prior to the executions of the warrants at issue [the ones issued for the searches in April] prosecutors obtained the entirety of Giuliani’s iCloud, which certainly had communications with, and on behalf of, the sitting President, containing material relating to the impending impeachment, the welfare of the country, and to national security,” the attorneys wrote in the letter, which was unsealed Monday.The lawyers asked Oetken to unseal the 2019 iCloud warrant so that they can review the legitimacy of affidavits that would have been filed as part of an application to a judge to get permission for prosecutors to seize Giuliani’s data while he was working for Trump.”Another reason Giuliani should be entitled to review the Government’s application is the possibility that information seized in secret and kept secret from Giuliani for a year and a half was leaked to the House Impeachment Committee,” the letter said.The lawyers told Oetken that they want him to first resolve whether prosecutors’ conduct regarding Giuliani has been legal before he considers whether to appoint a so-called special master to review material seized from Giuliani’s office and home. The special master would determine what information seized in the recent raid is privileged, and what can be turned over to federal investigators.”The validity of the 2019 covert warrant, and the handling of the information obtained by the prosecutor are serious questions that must be resolved before any further damage is done,” wrote the lawyers.”Moreover, the fruits of that 2019 search were certainly used in some part to secure the 2021 largely duplicative search warrant and subsequent seizures,” the letter said. “It is for those reasons that it is premature to consider a special master before these critical issues are resolved.”FBI agents seized electronic devices from Giuliani’s home and office during the searches on April 28.Giuliani’s lawyers said in their letter that they have “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 then, the failure to give notice to Giuliani and his clients, and withholding information about that search for 18 months.”CNBC PoliticsRead more of CNBC’s politics coverage:The lawyers also wrote that “during that period the government unilaterally reviewed all the information, privileged and not, and made entirely uninformed decisions about privilege (without any input from the clients or their counsel).””This was during a period when the President was under investigation by that very office and the Justice Department of which they are an integral part,” the letter said.In a separate letter, a lawyer for Republican attorney Victoria Toensing asked the judge to order the government to give back the materials that were seized from her in “covert” and “overt” searches.Like the letter from Giuliani, Toensing’s letter argued that she should be allowed to review whether the seized materials are covered by attorney-client privilege protections.NBC News reported that FBI agents executed a search warrant on Toensing’s Washington-area home on April 28, the same day that they raided Giuliani’s properties.Toensing’s letter specifies that electronic data had also been seized from her Google and iCloud accounts in “Covert Warrants” in 2019.Toensing’s lawyer, Michael Bowe, asks the judge to order the government to return her iPhone 7 as well as her Google and iCloud data, then give her time to process the data and determine which items are privileged before the government reviews it.”Whatever its motivation, this exercise by the Government flies in the face of the Sixth Amendment and the most sacred attorney-client privilege,” Bowe wrote. “At its core, this constitutionally intrusive exercise attempts to normalize a process that under all relevant jurisprudence, should not be, and indeed is not, normal.”Giuliani is being investigated by the U.S. Attorney’s Office for the Southern District of New York. He headed that federal prosecutors’ office before becoming mayor in 1993.