"Imperfect Justice: Prosecuting Casey Anthony" is the first book by a participant in the case to hit the stores. He calls Anthony's story that she had been sexually abused by her father a "nuclear lie," the Orlando Sentinel reported.
"I have seen my share of liars, but never one quite like this," he said.
Anthony's toddler daughter, Caylee, vanished in June 2008. When Anthony reported her missing a month later, she said she had been kidnapped by a non-existent nanny. Caylee's skeletal remains were found that December in a wooded area near the house where she and her mother had been living with her grandparents.
Ashton criticizes tactics used by the defense team, especially Anthony's lead lawyer, Jose Baez.
"In many ways, I think the defense came to mirror the client they represented," he said.
Ashton said he was "stunned" by the jury's decision to acquit Anthony of all counts, including murder, except lying to police.
"What I find truly baffling is that somehow they did not see proof enough to convict her of a lesser murder charge or even manslaughter," Ashton wrote.