Nothing makes people laugh like bioterrorism.

At least that's what hoaxsters capitalizing on the anthrax scare by pulling powder pranks seem to think. Since Sept. 11, officials across the country have responded to thousands of anthrax scares. In the past two weeks alone, postal inspectors have investigated 6,305 incidents, nearly all of them false alarms or practical jokes.

Sorry jokers, the feds are on to you and they are cracking down with stiff sentences.

"They should be prepared to face harsh consequences if they follow through with a hoax or a threat," Texas Attorney General John Cornyn said. "Today, as a nation at war, they will not be tolerated at all."

Attorney General John Ashcroft said those who fake anthrax or other terrorist scares will face federal prosecution. False threats of anthrax attacks are "grotesque transgressions of the public trust," Ashcroft said at a news conference.

"The threat of bioterrorism is no joking matter," he said, and the hoaxes tax the resources of an already overburdened law enforcement system.

Copycats across the country are trying to get a rise out of innocent civilians using powder, envelopes and other crude materials that simulate actual anthrax. Sometimes the pranks are even played on close friends, co-workers and family.

James Vasselli, 27, a county prosecutor in Chicago admitted that he placed an envelope full of sugar on the desk of fellow prosecutor Adam Weber. The envelope bore the return address of a person Weber was prosecuting. After tests showed that the powder was sugar, Vasselli admitted what he had done and resigned.

Officer Tom Donegan of the Chicago Police Department said, "We had quite a few of bomb scare and hazardous material and suspicious packages calls. During the week of Oct. 14 to 18 we had over 800 calls. That week was the busiest because that's when the anthrax started appearing in Washington," he said. All the calls turned out to be false alarms.

"We had two people arrested trying to play a hoax," Donegan said. One person addressed an envelope to his roommate and inside was a powdery substance and a letter making reference to Sept. 11. He has been arrested and charged with felony disorderly conduct.

A grocery store employee, who placed an envelope on her manager's desk and made a reference to anthrax, perpetrated the second hoax. "She was also arrested and charged," he said.

Even a man who answers the 911 calls has been caught doing the dirty deed.

Fireman Steve Welch, 37, started a scare with a simple comment to his buddies at the firehouse: He had opened a letter at home, and white powder had spilled out.

According to police he stood by silently as his fellow firefighters in Old Lycoming Township, Pa., rushed to scrub themselves and their station house down, health officials quarantined people who had gathered in a neighboring social hall and a hazardous material team sped to Welch's home. His two young children were stripped naked in freezing weather and hosed down in a plastic decontamination hut set up in the family's driveway.

Finally, Welch himself, dressed in only a beach towel, emerged from his home and took the cleansing shower himself. It wasn't until 12 hours after the initial report that police say Welch really came clean, admitting there was never any powder.

Welch was charged with making false reports, tampering with or fabricating evidence and criminal mischief for causing more than $5,000 in public funds to be spent. He has been released on $75,000 bail pending a Nov. 13 hearing.

Joseph Faryniarz, 48, an employee of the Connecticut Department of Environmental Protection, was charged with participating in an anthrax hoax that shut down the 808 agency for two days at an estimated cost of $1.5 million. Co-workers had to disrobe and were doused with a decontaminant. The "toxic" substance? Nondairy creamer.

Jim Turner, president of Los Angeles-based International Assessment Services Inc., has been helping clients deal with terrorist threats, both real and fake.

"People who engage in those kinds of hoaxes, they do it from a sense of needing to feel important," says Turner, who is in New York developing terror contingency plans. "This gives them a special status. 'Oh look. I'm one of the people, too. Pay attention to me. Be supportive of me. Be sympathetic of me. Think well of me.'"

These pranks usually start out somewhat innocently, Turner said, and then spiral out of control.

The Associated Press contributed to this report.