MIAMI — More than a decade after tabloid photo editor Robert Stevens became the first victim of the 2001 anthrax attacks, the U.S. government has agreed to pay his widow and family $2.5 million to settle their lawsuit, according to documents released Tuesday.

Stevens, 63, died on Oct. 5, 2001, when a letter containing deadly anthrax spores was opened at the then-headquarters in Boca Raton of American Media Inc., publisher of the National Enquirer, Sun and Globe tabloids. Eventually four other people would die, and 17 others would be sickened in similar letter attacks, which the FBI blames on a lone government scientist who committed suicide.

Stevens’ widow, Maureen Stevens, sued the government in 2003, claiming its negligence caused her husband’s death by failing to adequately safeguard anthrax at the U.S. Army Medical Research Institute of Infectious Diseases at Fort Detrick, Md. The FBI probe concluded that Fort Detrick was the source of the spores used in the attacks in New York, Washington and Florida.

The government failed to carry out its “duty of care, the highest degree of care” in making sure the deadly microbes were kept tightly under lock and key, said the lawsuit filed in West Palm Beach federal court.

The case languished for years in procedural delays and appeals until the FBI announced in 2008 that a Fort Detrick scientist, Dr. Bruce Ivins, was responsible for the attacks. Although some of his colleagues and outside experts have raised doubts about his intent and ability to weaponize the anthrax, the FBI formally closed its “Amerithrax” investigation in 2010.

Ivins killed himself with an overdose of Tylenol and valium as investigators closed in. His attorney has maintained Ivins is innocent, but Justice Department prosecutors say they had more than enough evidence to convict him at trial.

Stevens’ attorney, Richard Schuler, said when the FBI announced that Ivins was their man that it proved a key allegation in their lawsuit: “We’ve maintained all along this was an inside job,” he said. Schuler called the settlement a “tremendous victory” for the Stevens family after years of litigation.

“They fought us at every turn and dragged this thing out,” Schuler said. “You have to control access to these tremendously dangerous organisms, and they didn’t have any of that. You had security that was Swiss cheese out there.”