The former Army scientist identified by authorities as a "person of interest" in the 2001 anthrax attacks sued the New York Times Co. and columnist Nicholas D. Kristof yesterday, claiming the paper defamed him in a series of columns that identified him as the likely culprit.

The lawsuit, filed by Steven J. Hatfill in U.S. District Court in Alexandria, said Kristof identified him as the anthrax killer to "light a fire" under investigators in their probe of the anthrax-spore mailings, which killed five people and sickened 17. He accused Kristof of hurling "false and defamatory" allegations and the Times of engaging in "substandard and unethical journalism.''

In a series of columns in 2002, Kristof criticized the FBI for failing to aggressively pursue a scientist he at first identified as "Mr. Z.'' He wrote that the biodefense community had called Mr. Z a "likely culprit" and was "buzzing about Mr. Z behind his back," in part because the scientist was familiar with anthrax and was angered at the suspension of his top security clearance less than a month before the attacks.

Kristof, a Pulitzer Prize-winning journalist, later acknowledged that Mr. Z was Hatfill. He also wrote that Hatfill deserved the "presumption of innocence" and that "there is not a shred of traditional physical evidence linking him to the attacks.''

Kristof did not return a phone call to his office yesterday. A Times spokesman, Toby Usnik, said the newspaper "believes this case does not have merit. . . . We believe in a case like this, the law protects fair commentary on an important public issue."

The lawsuit was the latest attempt by Hatfill, 50, to defend himself since Attorney General John D. Ashcroft publicly called him a person of interest in the anthrax probe in 2002. A former researcher at the Army's infectious disease research laboratory at Fort Detrick in Frederick, Hatfill last year sued Ashcroft and the FBI in federal court in the District. He accused the government of conducting a "coordinated smear campaign" against him. A federal judge in March granted the government's request to postpone the suit for six months because the investigation was at a critical stage.

No one has been charged in the investigation of anthrax-tainted letters mailed to media and government offices.

Hatfill, who lives in the District and is unemployed, declined to comment. His suit said Kristof's "transparent identification of Dr. Hatfill, under the name of 'Mr. Z,' as the likely anthrax mailer, was baseless and false.''

Victor M. Glasberg, a lawyer for Hatfill, said he sent the Times a letter to the editor and an op-ed article detailing his concerns, but the Times rejected both.

"The problem here is not simply defamation. It is defamation plus the arrogance of power,'' Glasberg said in an interview, adding that the Times's role as "the most distinguished daily newspaper in America" ensured that Hatfill's reputation would be harmed.

Staff writer Allan Lengel contributed to this report.