[A]long the way, scores of others — terrorists, foreigners, academic researchers, biowarfare specialists and an elite group of Army scientists working behind high fences and barbed wire — drew the interest of the investigators. For some of them the cost was high: lost jobs, canceled visas, broken marriages, frayed friendships.

The director of the FBI's section on domestic terrorism says that investigations are "not always pretty."

"You try not to step on people’s toes, but sometimes it happens.”

It happens when you care more about solving the crime than about the lives you destroy in the process. Here's an example:

Early on, with more zeal than solid information, agents turned on three Pakistani-born city officials in Chester, Pa. One, Dr. Irshad Shaikh, was the health commissioner; his brother, Dr. Masood Shaikh, ran the lead-abatement program. The third, Asif Kazi, was then an accountant in the finance department.

Mr. Kazi was sitting in his City Hall office one day in November 2001 when F.B.I. agents burst in and began a barrage of questions. “It was really scary,” Mr. Kazi recalled in an interview last week. “It was: ‘What do you think of 9/11? What do know about anthrax?’"

Across town, an agent pointed a gun through an open window at Mr. Kazi’s home while others knocked down the front door as his wife was cooking in the kitchen. At the Shaikh brothers’ house, agents in bioprotection suits began hunting for germ-making equipment and carted away computers.

None of the three men had ever worked with anthrax. But for days, they were on national television as footage of the searches ran on a video loop and news announcers wondered aloud if they were the killers.

The result of the FBI's heavy-handed investigation:

The Shaikhs’ path to citizenship was disrupted, their visas ran out and both had to find work abroad, Mr. Kazi said. Mr. Kazi, already a citizen, was searched and interrogated for as long as two hours every time he traveled back from visiting his brother in Canada. Only about a year ago was his name removed from a watch list, allowing him to travel freely.

And then there's this:

Another casualty was Kenneth M. Berry, an emergency room physician with a strong interest in bioterrorism threats. In August 2004, agents raided his colonial-style home and his former apartment in Wellsville, a village in western New York, as well as his parents’ beach house on the Jersey Shore. ... “He was devastated,” Dr. Berry’s lawyer at the time, Clifford E. Lazzaro, said in an interview. “They destroyed his marriage and destroyed him professionally for a time.”

If Ivins' suicide is proof of his guilt, what should we make of Mikesell's reaction to being regarded as a suspect?

In 2002, Mr. Mikesell came under F.B.I. scrutiny, officials familiar with the case said. He began drinking heavily — a fifth of hard liquor a day toward the end, a family member said. “It was a shock that all of a sudden he’s a raging alcoholic,” recalled the relative, who spoke on the condition of anonymity because of family sensitivities.

This is the FBI's response to the agency's heavy-handed tactics:

[T]hey reject criticism from lawmakers and others about the conduct of the investigation and express no regret about those who were caught up in it.

FBI director Robert Mueller said Friday:

“I do not apologize for any aspect of the investigation,” he told reporters. It is erroneous, he added, “to say there were mistakes.”

Of course not. Because the FBI cares about clearing the case, not about whether they got the right guy, or destroy innocent lives in the process.