"At least whoever it was took it to what she thought was a safe haven," Paliotti said.
Watts said the firefighters who found the baby, who have since gone home and were not available for an interview, were "very upset" over the discovery.
"I know that some of them were obviously disturbed by it," she said. "Any time you have a death involving a child, it's not something that personnel take lightly."
She said detectives are reviewing surveillance video footage from the area for clues about who dropped off the baby, and when.
Investigators are asking that anyone with information about the incident call the Clearwater Police Department at (727) 562-4242 or the Clearwater police tip line at (727) 562-4080.
Women seeking a referral for counseling about a pregnancy can call the confidential hot line of A Safe Haven for Newborns at (877) 767-2229.