WASHINGTON — The F.B.I. is examining whether Theodore J. Kaczynski, the Unabomber, was responsible for lacing several bottles of Tylenol with cyanide in 1982, bringing together two of the highest profile domestic crimes of the late 20th century.

Mr. Kaczynski, who is serving a life sentence at the federal Supermax” prison in Florence, Colo., recently filed court papers disclosing that the Federal Bureau of Investigation’s Chicago office was looking into whether he could be linked to the unsolved killings of seven people who swallowed the poisoned medicine.

The F.B.I. “wanted a sample of my DNA to compare with some partial DNA profiles connected with a 1982 event in which someone put potassium cyanide in Tylenol,” Mr. Kaczynski wrote. “The officers said the F.B.I. was prepared to get a court order to compel me to provide the DNA sample, but wanted to know whether I would provide the sample voluntarily.”

In the handwritten filing, dated May 5, Mr. Kaczynski also denied any role: “I have never even possessed any potassium cyanide,” he wrote.

The F.B.I. office in Chicago announced in February 2009 that it was conducting a new review of evidence related to the Tylenol case, citing tips that had come in as a result of news media attention on the 25th anniversary of the killings and noting that “given the many recent advances in forensic technology, it was only natural that a second look be taken at the case and recovered evidence.”

Cynthia J. Yates, an F.B.I. spokeswoman in Chicago, confirmed that investigators were looking at Mr. Kaczynski. The development was first reported by The Sacramento Bee.

“As part of our re-examination of the evidence developed in connection with the 1982 Tylenol poisonings, we have attempted to secure DNA samples from numerous individuals, including Ted Kaczynski,” Ms. Yates said. “To date, Mr. Kaczynski has declined to voluntarily provide this sample. The investigation into the Tylenol murders remains ongoing.  No arrests have been made and no charges have been filed.”

Mr. Kaczynski wrote that he would be willing to provide a DNA sample voluntarily “if the F.B.I. would satisfy a certain condition that is not relevant here,” and that he did not explain. He also told the court that he was worried that there was a small chance that his DNA might match the partial profile collected in the Tylenol case by coincidence.

“If it happens by chance that I fit one of the partial DNA profiles that the F.B.I. has in relation to the 1982 cyanide incident, then it will be not only to my advantage, but to the advantage of society in general, to resolve correctly the question of any putative connection between me and the cyanide incident,” he wrote.

To help prove his innocence should that happen, he asked the court to order the government to preserve certain evidence collected in his own case that would show whether investigators had found any traces of cyanide, or written references to it, at his cabin in Montana after his arrest.

The United States Marshals on Wednesday opened an online auction for several of the items seized in the Unabomber case — including papers, tools, and clothing taken from Mr. Kaczynski’s cabin. The auction runs through June 2. A spokeswoman for the marshals said on Thursday that the auction was continuing and no items had been pulled from the sale.

On May 16, the United States attorney for the Eastern District of California, Benjamin B. Wagner, submitted a motion opposing Mr. Kaczynski’s request that a judge order the government to hold onto such evidence. Mr. Wagner argued that the courts had no authority to issue such an order.

“Kaczynski has not been indicted in connection with the Chicago Tylenol investigation, and no such federal prosecution is currently planned,” he wrote. “Consequently, there is no basis for an order interfering with the sale previously approved by the district court, as directed by the court of appeals.”

As the Unabomber, Mr. Kaczynski — a reclusive mathematician — was convicted of sending bombs through the mail for nearly 20 years, killing 3 people and wounding 23 others. In September 1995, both The New York Times and The Washington Post published excerpts of a manifesto he had written opposing modern technology and industrial society.

His brother recognized some of the ideas and phrases of the writings and tipped off authorities that Mr. Kaczynski might be the man they were seeking, and they arrested him at his remote cabin in rural Montana the following year.

In the Tylenol case, seven people in the Chicago area died in 1982 after taking Extra-Strength Tylenol capsules that turned out to be laced with cyanide. The killings prompted a massive recall of Tylenol products and led to the widespread use of tamper-resistant packaging.

Investigators eventually determined that someone had added poison to several medicine containers and put them back on the shelf in local stores. No one has ever been charged.