Investigators have old evidence, new ways to test old evidence and potential evidence they gathered Wednesday at the Massachusetts home of James Lewis.
Lewis was never charged in the deaths, but did go to prison for writing a related extortion letter.
Now the issue for police and forensic experts is whether evidence links anyone to the deaths.
Paula Prince was the last Tylenol victim, and the only one from Chicago.
Two months after her death, authorities arrested James Lewis who served time for writing an extortion letter to Johnson & Johnson, demanding 1 million dollars to stop the killings.
Richard Brzeczek knew the case first hand and was outspoken. He was Chicago's Police Superintendent at the time.
"I know back in '82 a lot of people thought he was the person who had contaminated the Tylenol, I never saw any evidence hooking him to the contamination," said Richard J. Brzeczek, former Chicago Police superintendent.
And, even though federal agents raided Lewis' Cambridge condo Wednesday, Brzeczek's opinion has not changed. He says it's easy to focus on the person - but it could be the wrong person. And only hard evidence can move this case forward.
"If you don't have that kind of evidence, you're not going any place," said Brzeczek.
The Tylenol was laced with cyanide. And anything investigators saved could be re-examined with improved or new technology to check fingerprints or DNA.
"Those two techniques are the most valuable for determining 'who done it' and both have advanced significantly over the last several decades," said Richard Bisbing, forensic scientist. "Therefore, those are the techniques you try to use on the evidence, if you still have it available."
Bisbing is with McCrone Associates in Westmont, which helped Johnson & Johnson create tamper-proof bottles after the seven deaths.
Bisbing says new, potential evidence, like anything Lewis may have written on his computer, must be scrutinized too.
"Like all statements and confessions, you have to look at what's been said and compare that with the evidence you have and see how consistent it is," said Bisbing.
The case must be built on facts. But even new developments raise hopes for the victim's families - hope that someone will be held responsible.
"Do I want it to be him? Yes, because then they have him," said Michelle Rosen, Tylenol victim's daughter.
Michelle Rosen says she's confused and is questioning what investigators have been doing all these years. She says if new technology was available for testing such as DNA why wasn't it used sooner.
Only investigators can answer that question, and they're not talking about the case.
Victim's daughter talks
Seven people in the Chicago area died after taking Tylenol capsules laced with cyanide.
ABC7 spoke with Michelle Rosen Thursday morning. She was only 8 when her mother collapsed and died after taking Tylenol. She said some of her family members were contacted by the FBI to inform them about the search Wednesday at James Lewis' home, the one-time leading suspect in the case. But, Rosen says with this latest break, it is raising more painful questions.
"If this is it, wonderful, not questioning who is it anymore," said Rosen, "but my confusion is, Has the FBI, the investigators been sleeping? This is the same person promised to us for 26 years that could not be the same person."
It is perhaps the same question other family members of the Tylenol murder victims are asking. James Lewis was the prime suspect 26 years ago when seven people from the Chicago area died after taking cyanide-laced Tylenol capsules.
Though he was convicted on extortion charges for sending a letter to Johnson & Johnson demanding a million dollars to stop the killings, and he served 12 years in prison for that, Lewis was never charged in the murders. There was not enough evidence.
Evidence is what investigators were looking for Wednesday. They removed boxes and a computer from the Cambridge, Mass., home of James Lewis. The FBI's Chicago office would only say that advances in forensic technology and other tips following the 25th anniversary of the deaths prompted agents to take another look.
The news is hitting home. Jack Eliason lost his sister Mary McFarland, who took Tylenol after lunch and died the next morning.
"I don't think the FBI is releasing a lot of info...sounds like something positive is happening," said Eliason.
But the haunting question, especially for Michelle Rosen, Why is it taking so long? She has grown from an 8-year-old to a mother herself. In a few months, she reminded, her mother will have been gone for 27 years. She died at 27, leaving four young children, who were robbed of a lifetime of memories.
"I really wish I had more to tell you. Sad that I don't have any stories, that this was taken away from me from someone who didn't even know her," Rosen said.
Rosen has not heard directly from investigators. She did say she would be excited if this indeed is the final break in the case. She says she is not looking for closure, there may be no such thing for her, but she is hoping for peace for her and all the other victims' families.
Rosen said she does not give her children any over-the-counter medicine.