The term "person of interest" seems to be attracting more interest in law enforcement these days.

The phrase has been thrown around by the media, police and government officials over cases ranging from the war on terror to missing children's cases. But what does it really mean?

Perhaps the country's best-known "person of interest" these days is Steven Hatfill, the scientist being investigated by the FBI in relation to last year's anthrax attacks. He's one of 20-30 "people of interest" in that case, though no other names have surfaced.

Hatfill, who says the federal government has ruined his life by linking him to the probe, was fired Tuesday from his job as a researcher at Louisiana State University.

The firing came after the Justice Department asked the school not to use him on any projects funded by grants from the agency. LSU's National Center for Biomedical Research and Training receives most of its funding from the Justice Department, according to a school official.

Hatfill addressed the term itself recently, saying, "I do not object to being considered a subject of interest by the authorities because of my knowledge and background in the field of biological warfare defense." But he did object to what he called the "outrageous official statements, calculated leaks to the media and causing a feeding frenzy operating to my great prejudice."

The FBI claims the term didn't come from them.

"It was used as a descriptive term by somebody in the media to term what is transpiring," said FBI spokesman Paul Moskal. "As far as I know, as best I can tell, it wasn't somebody from this office who first coined this phrase."

The FBI uses more "factual" terms to describe people they are interested in, Moskal said, such as "subjects of investigation" or a "person who's responsible."

But Robert Jordan, head of the FBI's Information Sharing Task Force, told a Senate Judiciary subcommittee in April he used the term "person of interest" and "individuals of investigative interest."

In another case, Omaha, Neb., FBI agent Jim Bogner described Luke Helder of Pine Island, Minn., as a "person of interest" earlier this year when Helder was arrested for a string of pipe bombings.

But still, the FBI refuses to explain just what a "person of interest" is.

Local law enforcement agencies have also used the term in various investigations. As far back as 1986, Ernest W. "Bill" McLean was called a "person of interest" when he was arrested in connection with the Green River killings, a string of murders in Washington state.

Mohamed el-Atriss, arrested recently for allegedly providing fake IDs to the Sept. 11 hijackers, was also called a person "of interest" by Michael Drewniak, a spokesman for the U.S. Attorney's office in Newark, N.J.

Not surprisingly, many defense attorneys have a problem with that.

"In the industry, it's just an out-and-out lie," said Washington attorney Bernard Grimm. "Behind the scenes, they think you're a suspect. But they don't call you that because then they lawyer up."

Grimm and others have drawn parallels between Hatfill's situation and that of Richard Jewell, the security guard suspected to have been responsible for the detonating a bomb during the 1996 Summer Olympics in Atlanta.

"Once you have connected a private citizen under investigation with a high-profile crime, everything that is published about that person and that person's life is potentially subjected to a 10,000 magnification," said L. Lin Wood, Jewell's Atlanta lawyer.

Jewell was never formally referred to as a suspect on the record by the FBI, but was termed a "possible suspect" or a "potentially valuable witness," Wood said. "What may be a totally innocuous event in a person's life can take on a somewhat sinister connotation."