Lewis has maintained that he could not have committed the crime because he was in New York at the time. But Nelson told ABC News that, based on an analysis of the stores where the tainted Tylenol was purchased, many close to the case believed that whoever dropped the drugs off had flown into Chicago, rented a car, gone and distributed the pills, and then flown back out of O'Hare airport.
A drug store surveillance photo captured an image of a bearded man who some said resembled Lewis.
The case caused a national panic and led to drastic changes in the way over the counter medicine is sold in this country, introducing "tamper-proof" packaging.
On a website, Lewis has posted an audio message which claims he has been misunderstood. "Many enjoy twisting and contorting what I say into something ominous and dreadful which I do not intend. That, my friends, is the curse of being labeled the Tylenol Man," he said.
In a statement released Wednesday, the FBI said the recent 25th anniversary of the crime prompted "many" new tips in the case.
"All of these tips have been or will be thoroughly investigated in an effort to solve this crime and bring some measure of closure to the families of the victims," the statement read. FBI officials said no arrests are imminent and characterized Wednesday's raid of Lewis' home as part of "an ongoing criminal investigation."
To date no one has been charged in the murders of the seven people who were killed in the Chicago area after swallowing the tampered capsules.
The poisonings all occurred in the Chicago within weeks of each other in the fall of 1982. Investigators at the time believed that the perpetrator had taken Tylenol packages from local supermarkets and drug stores, adulterated the contents, and later returned the Tylenol the store shelves.
Now, the new leads are sparking hope that the case will finally be solved.
"I hope they have new solid evidence because the person that did this should really be penalized," said Nelson. "He took a number of lives and, to date, has gotten away with it."
Avni Patel and Megan Chuchmach contributed to this report.