How the Florida man who died from a rare form of anthrax contracted the disease continues to baffle investigators, even after they retraced his last weeks and searched his workplace and home for clues.

No other cases of anthrax have been reported, Barbara Reynolds, a spokeswoman for the Centers for Disease Control and Prevention in Atlanta, said Friday.

There is no evidence that the death of Bob Stevens, the first fatality from inhalation anthrax in the United States in 25 years, is linked to terrorism.

The 63- year-old photo editor for the supermarket tabloid The Sun suffered cardiac arrest and died Friday after he didn’t respond to antibiotics and his kidneys failed.

Officials believe Stevens contracted anthrax naturally in Florida, said Dr. Steve Wiersma, an epidemiologist with the state Department of Health. The FBI is assisting in its investigation into the source of the exposure as a precaution.

Anthrax has been developed by some countries as a possible biological weapon, and the Sept. 11 terrorist attacks have put many people on edge about the threat. But anthrax can also be contracted naturally, often from farm animals or soil. Stevens was described as an avid outdoorsman who enjoyed fishing and gardening.

A team of FBI, CDC and state health and agriculture investigators searched Stevens' house for about two hours Friday. Tim O'Connor, a Palm Beach County health department spokesman, said some of the 50 health and law enforcement officials working the investigation also searched his workplace.

Investigators took a number of items from Stevens' home, including pesticide sprays and fertilizer bottles, to see if they were contaminated, officials said.

"We don't expect any of these to turn out positive, but those are prudent to check," Wiersma said.

Anthrax is not normally found among wildlife or livestock in Florida, said Dr. Paul Nicoletti, a veterinary professor at the University of Florida. He said anthrax occasionally appears among animals in Texas, Louisiana, New Mexico, Arkansas and parts of Midwest. Stevens visited North Carolina last month, but officials there said the disease is rare among animals in their state.

Only 18 inhalation cases in the United States were documented in the 20th century, the most recent in 1976 in California. The last anthrax case in Florida was in 1974, according to the state health department.

Some in Lantana were concerned because suspected hijacker Mohamed Atta rented planes in August at a flight school located at a county airport within a mile of Stevens' home.

Atta also visited an airfield in Belle Glade, about 40 miles inland from Lantana, and asked workers questions about their crop sprayers, but never flew one. Some of the suspected hijackers had lived in an apartment complex in Delray Beach, about 10 miles south of Lantana.

"I am nervous, what if it's in my soil? I have a dog and I have kids," said Cathy Saulter, 39, who lives across the street from Stevens.

The Associated Press contributed to this report.