The FBI finally believes it fingered the culprit of the 2001 anthrax attacks. According to the Los Angeles Times, which broke the story, the government was "about to file criminal charges" against a former top government scientist, Bruce E. Ivins, who died Tuesday of an apparent suicide:

Ivins, whose name had not been disclosed publicly as a suspect in the case, played a central role in research to improve anthrax vaccines by preparing anthrax formulations used in experiments on animals.

Regarded as a skilled microbiologist, Ivins also helped the FBI analyze the powdery material recovered from one of the anthrax-tainted envelopes sent to a U.S. senator's office in Washington.

Citing a "U.S. official," the Associated Press says prosecutors "had planned to seek indictment and the death penalty" against Ivins.

Investigators first began to focus on Ivins nearly two years ago after new agents were brought in to lead the investigation. According to the Times, investigators questioned Ivins years ago -- and missed key clues:

Ivins, employed as a civilian at Ft. Detrick, earlier had attracted the attention of Army officials because of anthrax contaminations that Ivins failed to report for five months. In sworn oral and written statements to an Army investigator, Ivins said that he had erred by keeping the episodes secret -- from December 2001 to late April 2002. He said he had swabbed and bleached more than 20 areas that he suspected were contaminated by a sloppy lab technician....

Ivins' recollections should have raised serious questions about his veracity and his intentions, according to some of those familiar with the investigation. For instance, although Ivins said that he swabbed areas near and within his personal office, and bleached surfaces to kill any spores, and that some of the swabs tested positive, he was vague about what should have been an essential next step:

Reswabbing to check whether any spores remained.

"I honestly do not recall if follow-up swabs were taken of the area," Ivins said. "I may have done so, but I do not now remember reswabbing."

"That's bull----," said one former senior USAMRIID official. "If there's contamination, you always reswab. And you would remember doing it."

Of course, the government -- and many in the media -- had initially focused on another government scientist, Steven Hatfill. He was famously dubbed a "person of interest" by then-Attorney General John Ashcroft. A month ago, the Justice Department settled a lawsuit from Hatfill for nearly $6 million. According to the Times, the deal was "an essential step to clear the way for prosecuting Ivins."

The LA Times reporter who broke the story, David Willman, also had a piece in June exploring just how deeply the FBI had once botched the investigation:

Behind the scenes, FBI agents chafed at their supervisors' obsession with Hatfill. The preoccupation with Hatfill persisted for years, long after investigators failed to turn up any evidence linking him to the mailings. Other potential suspects and leads were ignored or given insufficient attention, investigators said.

Ivins lived about 200 miles from the area in New Jersey where most of the letters were postmarked. (Experts have long suspected that the anthrax attacker was a government scientist who meant to draw attention to the dangers of anthrax -- and didn't mean to kill anybody. For instance, the first letters warned people to take penicillin.)

According to the AP, in 2003 Ivins also "received the highest honor given to Defense Department civilian employees for helping solve technical problems in the manufacture of anthrax vaccine."

UPDATE: Ivins' lawyer has released a statement asserting his client's innonence:

For six years, Dr. Ivins fully cooperated with that investigation, assisting the government in every way that was asked of him. He was a world-renowned and highly decorated scientist who served his country for over 33 years with the Department of the Army. We are saddened by his death, and disappointed that we will not have the opportunity to defend his good name and reputation in a court of law. We assert his innocence in these killings, and would have established that at trial.

Matthew Schwarzfeld helped research this story.