VOLUSIA COUNTY, Fla. -

He claims his findings were changed after he was fired, and now the medical examiner who performed the autopsies of two high-profile cases in Central Florida is speaking out.

In his book, "Dead Men Can't Lie: The Truth Behind the Cases of Trayvon Martin and Marlon Brown," Dr. Shiping Bao said he wasn't able to present all his evidence during George Zimmerman's trial.

Bao, now working as an independent forensic pathologist in Illinois, was fired as Associate Medical Examiner in Volusia County shortly before the office released the findings of Brown's autopsy.

Bao said he determined Marlon Brown's cause of death was "traumatic asphyxia."

He said he watched the dash cam video from the officer's patrol car and completed the autopsy in three weeks, but he said Dr. Marie Herrmann, chief medical examiner, held onto the report and fired him.

The final autopsy report, signed by Hermann and released four months after Brown was killed, said the cause of death was mechanical asphyxia.

"I believe that you have a whole different set of emotions when you hear mechanical asphyxia versus traumatic asphyxia," said Krystal Brown, Marlon Brown's ex-wife.

Herrmann's report said Marlon Brown was not struck by the patrol car, but that he "slipped and fell and then the police car came to a stop on top of him."

However in his book, Boa said Brown was struck by the officer's vehicle and that Brown, "suffered beneath the car for a long time before dying."

"The county has complete confidence in the performance of Dr. Marie Herrmann, a medical examiner with many years of experience in her field and a track record of excellence that speaks for itself," said County spokesman Dave Byron in a statement to Local 6. "The county gives no credence to the comments of a disgruntled former employee."