A former employee of Johnson and Johnson has written a book about the infamous Tylenol murders in which he claims it was an inside job.
The 1982 Tylenol poisonings killed seven people in the Chicago area.
Scott Bartz's book The Tylenol Mafia was released on Monday.
Bartz said he's convinced that the Tylenol killer worked in Johnson and Johnson's distribution chain, owned cyanide, and made threats.
"He was an angry man," Bartz said, who was later convicted for a separate murder.
He also accuses Johnson and Johnson of a cover-up to avoid liability.
That suspect has since died.
Johnson and Johnson said that Bartz's theory has no merit.
The FBI says its Tylenol investigation is still active, but so far, no one has come forward with enough evidence to bring charges.
Bartz currently has two unrelated lawsuits pending against Johnson and Johnson.