Shiping Bao testifies during the George Zimmerman trial in Sanford, Florida, on Friday, July 5.
CNN  — 

Shiping Bao, the medical examiner for the Trayvon Martin case, has been fired.

Bao was let go from the Volusia County Medical Examiner’s Office last week, officials said Wednesday.

Authorities provided a copy of his termination letter, but did not specify a reason.

The letter says Bao was given a choice to resign.

He didn’t. So, he was terminated Friday.