The Justice Department yesterday closed the case, announcing the late 'Dr. Ivins was the only person responsible for these attacks.'

Ivins passed the first polygraph to satisfy a security requirement prior to working with the FBI as part of a team of scientists at the Fort Detrick, Md., lab who originally helped analyze the anthrax letters. He passed a second exam after he became a suspect.

WND has learned that the FBI was so frustrated with the exam results that last October authorities asked a judge for permission to search Ivins' home and vehicles specifically for evidence of any materials, such as books, that would have helped him 'defeat a polygraph.'

Also, officials confirm that FBI handwriting analysts were unable to conclusively match samples of Ivins' handwriting with the writing on the anthrax envelopes and letters, which sounded as if they were written by jihadist accomplices of the 9/11 hijackers. The crude notes declared: 'DEATH TO AMERICA. DEATH TO ISRAEL. ALLAH IS GREAT.'

Investigators also failed to uncover other critical evidence linking Ivins directly to the letters. For instance:

• No textile fibers were found in his office, residence or vehicles matching fibers found on the scotch tape used to seal the envelopes;
   
• No pens were found matching the ink used to address the envelopes;
   
• Samples of his hair failed to match hair follicles found inside the Princeton, N.J., mailbox used to mail the letters.

Also, no souvenirs of the crime, such as newspaper clippings, were found in his possession as commonly seen in serial murder cases.

What's more, the FBI could not place Ivins at the crime scene with evidence, such as gas station or other receipts, at the time the letters were mailed in September and October 2001.

While acknowledging the circumstantial nature of their case against Ivins, prosecutors argue they're confident they would have been able to prove his guilt 'beyond a reasonable doubt' in court.

They say they used new forensic technology to narrow the deadly spores used in the attacks down to a batch stored in Ivins' lab. However, they concede that more than 100 other people – including some Arab-American scientists – had access to the batch and that the virulent Ames strain was found elsewhere.

Also, the FBI sent the anthrax letters to the same lab for analysis within days of the attacks, which might explain the match.

Still, prosecutors also point to the fact that Ivins spent an inordinate amount of time working in his lab in the days before the attacks, possibly preparing the poison. They say the number of his late nights spiked in September and October of 2001.

They cite an e-mail Ivins wrote to a colleague in which he expressed anger toward the 9/11 terrorists but also toward those in government who didn't do enough to protect the country. Prosecutors speculate one of the reasons he targeted Democratic leaders in Congress was because he felt they were soft on terrorism.

However, lab records reviewed by WND show the number of late nights Ivins put in at the lab first spiked in August 2001, weeks before the 9/11 attacks.

Ivins told FBI agents that he was putting in more late hours to escape problems at home, an explanation prosecutors found 'unsatisfactory.'

Prosecutors highlighted another Ivins' e-mail to a colleague in which they say he used language similar to the threats used in the anthrax letters. The partial text of the quote the officials first leaked to the media was 'Bin Laden terrorists for sure have anthrax' and have 'just decreed death to all Jews and all Americans.'

However, the full text of the first line of the e-mail cited in the government affidavit for a search warrant read as follows: 'I heard tonight that Bin Laden terrorists for sure have anthrax and sarin gas.' (The e-mail was sent after 9/11 when al-Qaida was in the news.) The next line in the e-mail begins, 'You ... ' followed by a blacked-out line.

Prosecutors redacted the rest of the sentence from the copy of the affidavit unsealed for the press. The government did not provide an explanation.

Ivins, in an apparent suicide, last week overdosed on Tylenol 3 with codeine. His lawyers say he was depressed and driven to suicide by overly aggressive FBI agents who stalked him and his family.

They say the government's case against him amounted to 'heaps of innuendo' and that their client would have been acquitted if he had survived. They point out that the government's evidence was not even strong enough to present to a grand jury, let alone a trial jury.

Indeed, prosecutors had not delivered the case to a grand jury for indictment. And the Pentagon had not revoked Ivins' security clearance.

Prosecutors were equally confident another scientist, Steven Hatfill, was the anthrax culprit before recently agreeing to pay him $6 million in damages.