Able Danger issue. Snopes.com clarified a widely circulated email that claimed the two Attas were one and the same. Another variation of the Two Attas theory reported by Kaus notes that Omar Abdel Rahman also had an associate with the name Mohamed El-Amir (a name sometimes used by Atta) who was not the Mohamed Atta involved in the 9/11 hijacking. However, Shaffer clarified that. He told 9/11 Commission staffers Able Danger identified three of the individuals in the terrorist cells that conducted the 9/11 attacks, to include Atta - Shaffer did not mention the names of any other of the 9/11 hijackers in his disclosure to the 9/11 staff. A fourth 9/11 terrorist came from the second cell. Eric Umansky states the problem this way: "In fact, the two-Atta theory only leaves one major issue unexplained: What about the three other 9/11 hijackers that Able Danger purportedly fingered? The Department of Defense released a report addressing the issue of two possible individuals with the last name of Atta and explaining that it was basically a clerical error. When we reviewed INS records, they appeared to reflect two entries by Atta into the United States on January 10, 2001, which initially raised a question as to whether Atta had entered twice on the same day or whether a second person posing as Atta also entered on January 10, 2001. The NIIS printout for the first entry reflects that Atta entered with an admission period of January 10, 2001, to September 8, 2001 (admission number 68653985708). The second record reflects a second entry on January 10, 2001, with an admission period from January 10, 2001, to July 9, 2001 (admission number 10847166009). However, this occurred because the inspector at the Miami District Office who changed Atta's admission date failed to follow the proper procedure to ensure that the previous entry would be corrected, and a new entry was created in NIIS. The inspector sent the old I-94 and the corrected I-94 to the contractor which data enters I-94s for the INS. The May 2, 2001, transaction with Atta was data entered and then uploaded to NIIS as if it were a new entry by Atta. This happened because the inspector issued a new I-94 with a new admission number on it. To prevent two entries from occurring in NIIS, the inspector should have crossed out the admission number on the new I-94,