Authorities in Chicago are sifting through new evidence seized in the Boston area as part of an investigation into the 1982 Tylenol poisonings that left seven people dead, an FBI spokesman told a radio station Wednesday.

A week ago authorities seized a computer and boxes of files from James W. Lewis' Cambridge, Mass., home. The sudden flurry of activity has raised hopes of a long-awaited break in the case.

Investigators returned to Chicago last weekend from the Boston area, and began sorting through the evidence on Monday, FBI spokesman Ross Rice told WBBM Radio.

"They brought with them the items that were recovered during the search, and they're now involved in the process of going through, very meticulously, all of those items to try to determine if there's any link to our investigation," Rice said.

A message left after business hours Wednesday at the Chicago FBI's media office was not immediately returned.

Lewis served more than 12 years in prison for trying to extort money from Tylenol's manufacturers. No one was ever charged in the seven cyanide deaths.

Lewis was free Wednesday and has not been charged with anything, Rice said.

Exactly why investigators have suddenly taken so much interest in the self-proclaimed "Tylenol Man" is unclear, but last week the FBI cited advances in forensic technology, along with publicity and tips that came in around the 25th anniversary of the crime in 2007.

In a space of three days beginning Sept. 29, 1982, seven people who took cyanide-laced Tylenol in Chicago and four suburbs died. That triggered a national scare and a huge recall, and eventually led to the widespread adoption of tamperproof packaging for over-the-counter drugs.

Caught after a nationwide manhunt in late 1982, Lewis gave investigators a detailed account of how the killer might have done it, and eventually admitted sending a letter demanding $1 million from the manufacturer of Tylenol to "stop the killing."

But he said he was only trying to exploit the crisis, and denied he had anything to do with the deaths. He was convicted of extortion in 1983 and spent 12 years in prison, getting out in 1995.