Two autopsies ruled it a suicide. But relatives of the first black person elected mayor of this mostly white town still believe he was murdered.
Gerald Washington was found dead Dec. 30, 2006, with a gunshot to the chest, his gun nearby. No suicide note was found.
Autopsies by state police and the local coroner determined Washington killed himself. The district attorney has said he plans to close the case.
But a third autopsy is now planned after Wednesday's scheduled exhumation of Washington's body. Washington's family hired renowned forensic pathologist Cyril Wecht to perform the procedure.
Wecht said a third autopsy is highly unusual in any circumstance, the AP reports.
"I have been involved in less than a handful in 45 years where a third autopsy is done. Yes, that is rare," he said in a telephone interview.
Washington's widow, Mary, has said she believes her husband was murdered and that the killing was covered up as part of a conspiracy, the AP reports.
Washington won with 69 percent of the vote last year over a white candidate. The 57-year-old had not yet taken office when his body was found in the parking lot of a former high school, his alma mater.
Lawrence Morrow, a spokesman for the Washington family, said the body will be taken to Houston, then flown to Pittsburgh for the autopsy at Wecht's lab.
Wecht has worked as a consultant on cases including Elvis Presley's death and the slayings of JonBenet Ramsey and Laci Peterson. Last year, he performed an autopsy on Anna Nicole Smith's 20-year-old son.
Westlake is 80 percent white, a refinery town with a population of 4,500, about 140 miles (225 kilometers) east of Houston.