The person was not authorized to speak publicly before the news conference and talked on condition of anonymity. Attorneys for Herold and victim Charla Nash said they had no knowledge of the decision and couldn't comment on it.
The 200-pound chimpanzee went berserk after Herold asked Nash to help lure him back into her house. The chimp ripped off Nash's hands, nose, lips and eyelids.
Nash revealed her heavily disfigured face last month on "The Oprah Winfrey Show."
Nash's family is suing Herold for $50 million and wants to sue the state for $150 million. Nash's family has said Herold was negligent and reckless for lacking the ability to control "a wild animal with violent propensities."
A biologist for the state Department of Environmental Protection warned officials before the attack that Travis could seriously hurt someone if he felt threatened, noting that he was large and strong.
Herold's attorney has called the attack work-related and said her family's case should be treated like a workers' compensation claim. The strategy, if successful, would limit potential damages in the case and insulate the chimp owner from personal liability.
Test results showed that Travis had the anti-anxiety drug Xanax in his system.
The animal, which was shot and killed by police, had also escaped in 2003 from his owner's car and led police on a chase for hours in downtown Stamford. No one was injured.
Records obtained by The Associated Press through an open-records request show the state began receiving warnings immediately after that event.
Nash's attorney has said the environmental department had information for at least five years that would have allowed the agency to remove Travis from the home.
Environmental protection officials have said that during the 13 years Travis was with Herold, the agency received only a few inquiries about the chimp among thousands in general about possession of wild animals.
They said the memo from the biologist underscored the need for a clear, new law that would forbid ownership of potentially dangerous animals as pets and impose stiff penalties for those possessing them, and they blamed the failure to act on a communications problem and a lack of expertise in exotic animals at the agency.