Peerwani and county officials had not previously announced the retirement but confirmed it on Friday.
Peerwani has been Tarrant County medical examiner since July 1979 and also serves as medical examiner for Parker, Denton and Johnson counties.
In November, Peerwani suspended his longtime top deputy, Dr. Marc Krause, from doing autopsies in murder cases after Krause missed a bullet in an exam and the victim’s body had to be exhumed. Peerwani later audited Krause’s work in 40 death investigations and found Krause made 59 mistakes. Krause left the office earlier this month.
Dallas County District Attorney John Creuzot was appointed special prosecutor and is investigating.