"During her interview, she would constantly change what she was saying based on the line of questioning," Slaughter said. "There was no feeling with them that there was any remorse, only her attempting to escape the reality of the story by making things up as she went."
Slaughter also addressed a sketch released Monday about a possible suspect named Antwan who abducted Belliveau.
"We do not believe there was an Antwan," Slaughter said. "We don't believe there was a white [Toyota] Camry -- that was all fabricated by Ms. Stinson to help cover her alibi what she'd actually done."
A statewide Amber Alert was initially issued for Belliveau, but was called off when his body was found in a wooded area.
Police said they are still looking a different person, seen on gas station surveillance, who they believe may be a witness with valuable information about what happened.
"Her story about being in [Largo] Central Park was a deception on her part," Slaughter said. "In subsequent interviews she admitted she made up the story. The injuries were, by her own admission, self inflicted. In the time in question when she stated she was unconscious in the park, she was actually at another location, which is where we subsequently found the body."
Slaughter could not go into specifics into what information they received that led them to Belliveau's body.
Stinson will appear in court Wednesday afternoon. She has been charged with first-degree murder.
Investigators do not believe anyone else was involved.
The investigation is still active and ongoing.
Slaughter said DCF had been involved in an investigation with the family, but had seen Belliveau the Friday before he died.