While monitoring foreign terrorists in the US, the FBI listens to calls made by suspects as a part of an operation called Catcher’s Mitt, which is curtailed at this time due to misleading statements by FBI agents. It is never revealed who the targets of the FBI’s surveillance are under this operation, but below are some of the terrorism suspects under investigation in the US at the time: 
Imran Mandhai, Shuyeb Mossa Jokhan and Adnan El Shukrijumah in Florida. They are plotting a series of attacks there, but Mandhai and Jokhan are brought in for questioning by the FBI and surveillance of them stops in late spring (see November 2000-Spring 2002 and May 2, 2001); Another Florida cell connected to Blind Sheikh Omar Abdul-Rahman. The FBI has been investigating it since 1993 (see (October 1993-November 2001)); Al-Qaeda operatives in Denver (see March 2000); A Boston-based al-Qaeda cell involving Nabil al-Marabh and Raed Hijazi. Cell members provide funding to terrorists, fight abroad, and are involved in document forging (see January 2001, Spring 2001, and Early September 2001); Fourteen of the hijackers’ associates the FBI investigates before 9/11. The FBI is still investigating four of these people while the hijackers associate with them; [US Congress, 7/24/2003, pp. 169 
] Hamas operatives such as Mohammed Salah in Chicago. Salah invests money in the US and sends it to the occupied territories to fund attacks (see June 9, 1998).
When problems are found with the applications for the wiretap warrants, an investigation is launched (see Summer-October 2000), and new requirements for warrant applications are put in place (see October 2000). From this time well into 2001, the FBI is forced to shut down wiretaps of al-Qaeda-related suspects connected to the 1998 US embassy bombings and Hamas (see March 2001 and April 2001). One source familiar with the case says that about 10 to 20 al-Qaeda related wiretaps have to be shut down and it becomes more difficult to get permission for new FISA wiretaps. Newsweek notes, “The effect [is] to stymie terror surveillance at exactly the moment it was needed most: requests from both Phoenix [with the Ken Williams memo (see July 10, 2001)] and Minneapolis [with Zacarias Moussaoui’s arrest] for wiretaps [will be] turned down [by FBI superiors],” (see August 21, 2001 and August 28, 2001). [Newsweek, 5/27/2002] Robert Wright is an FBI agent who led the Vulgar Betrayal investigation looking into allegations that Saudi businessman Yassin al-Qadi helped finance the embassy bombings, and other matters. In late 2002, he will claim to discover evidence that some of the FBI intelligence agents who stalled and obstructed his investigation were the same FBI agents who misrepresented the FISA petitions. [Judicial Watch, 9/11/2002]
March 2001: Justice Department Investigation Finds FISA Applications Are Misleading
The Justice Department’s Office of Intelligence Policy and Review (OIPR) discovers that an application for a warrant under the Foreign Intelligence Surveillance Act (FISA) is misleading. The application is for surveillance of the Palestinian militant group Hamas and the supporting affidavit was signed by FBI agent Michael Resnick. The Justice Department’s Office of Professional Responsibility (OPR) is already investigating dozens of similar errors in FISA warrants for surveillance of al-Qaeda targets in the US (see Summer 2000-September 11, 2001). The application is misleading because its does not accurately describe the “wall” procedures being followed by several FBI field offices. Wall procedures regulate the passage of information from FBI intelligence agents to FBI criminal agents and local US attorneys’ offices. The misleading description is also found in another 14 warrant applications for surveillance of Hamas. The impact of the misleading statements in the Hamas investigations has not been disclosed, but in the al-Qaeda cases the wall was breached because criminal agents had unrestricted access to intelligence information (see Summer-October 2000). Royce Lamberth, Presiding Judge on the FISA Court, writes to Attorney General John Ashcroft saying it will no longer accept any applications where the supporting affidavit is signed by Resnick and asking for an immediate inquiry. [Foreign Intelligence Surveillance Court, 3/9/2001 ; New York Times, 9/19/2001; New York Times, 5/27/2002; Washington Post, 8/23/2002; Arab News, 3/3/2004; US Department of Justice, 11/2004, pp. 39 ] The Justice Department’s investigation into the misleading applications finds that “none of [them]… were the result of professional misconduct or poor judgement,” but that “a majority of the errors were the result of systemic flaws.” [US Department of Justice, 11/2004, pp. 40 ] Following the discovery of the errors in the FISA applications, surveillance of al-Qaeda and Hamas targets in the US is curtailed (see April 2001). Resnick remains with the bureau and will become head of the Joint Terrorism Task Force in North Carolina and then chief of the Terrorist Identities Group at the FBI’s National Counter Terrorism Center. [US Congress, 3/30/2006; WCNC, 6/20/2006]
Shortly After 9:37 a.m.: FISA Judge Grants Five Warrantless Surveillance Requests Minutes after Pentagon Attack
Royce Lamberth, head of the FISA court which grants warrants for intelligence cases, grants five warrantless surveillance requests minutes after the Pentagon attack. Lamberth will later report being stuck in a carpool lane near the Pentagon when it is hit. With his car enveloped in smoke, he calls US marshals to help him get to his office. Lamberth will later say that by the time officers reached him, “I had approved five FISA coverages [warrants] on my cellphone.” [Associated Press, 6/24/2007] Presumably this represents the start of a flurry of surveillance activity in response to the 9/11 attacks, but it is not known who was to be monitored or how their names were learned and acted on so quickly.
