Live

Watch CBSN Live

Shiping Bao, medical examiner in Trayvon Martin case, fired

Shiping Bao testifies during the George Zimmerman trial in Seminole circuit court, July 5, 2013 in Sanford, Florida. Gary W. Green-Pool/Getty Images

(CBS/AP) ORLANDO, Fla. - The medical examiner that performed Trayvon Martin's autopsy and offered conflicting testimony at George Zimmerman's murder trial has been relieved of his position.

PICTURES: George Zimmerman crime scene photos

According to a letter released by Volusia County on Tuesday, Shiping Bao was fired from his position as an associate medical examiner last week. Spokesman Dave Byron declined to give a reason, citing county standard personnel practices.

In the Aug. 23 letter, Bao was granted 30 days to find employment at another office, and he declined to resign at the end of that period. An attorney Bao has retained didn't immediately return a message.

Bao began his employment with Volusia County in July 2011 and made an annual salary of $175,950.

Trayvon Martin suffered after gunshot, medical examiner says

During Zimmerman's trial, Bao changed his original opinion about how long Martin lived after being shot. Bao initially estimated that Martin lived from one to three minutes after Zimmerman shot him, but later testified the Florida teen had lived up to 10 minutes. Bao said he had changed his opinion three weeks before the trial based on another case that was similar to Martin's.

When questioned by Zimmerman's defense whether he had informed prosecutors about his new opinion, Bao said he had not.

In court, Bao said he didn't "see the problem" in changing his opinion.

"If you have new information, new experiences, you read a new book, you change your opinion," Bao said. "If someone never changes opinion, you can call them mentally retarded. You never learn, right?"

Zimmerman's defense attorney Don West also grilled Bao in court about changing his analysis of Martin's toxicology tests. Bao initially told attorneys the results indicated marijuana was present in Martin's system, but said the amount of the drug wouldn't have a physical, emotional or mental effect.

However, Bao said that after spending "hours and hours" on new research in preparing for the trial, he decided that the marijuana "could" have had an effect on Martin.

Zimmerman, a 29-year-old neighborhood watch leader in Sanford, Fla., was charged with second-degree murder in the shooting death of the 17-year-old Martin during an altercation last year in a gated community. He pleaded not guilty, claiming he shot the teen in self-defense. He was acquitted July 13.

Complete coverage of the George Zimmerman Trial-Trayvon Martin case on Crimesider