The Georgia Bureau of Investigation conducted an autopsy Thursday on a judge who was found dead in his car, and preliminary results suggest death by suicide, a spokesman said Thursday.

The Spalding County Sheriff's Office asked the GBI Tuesday to investigate the death of Griffin Municipal Court Judge William G. Johnston, age 53.

According to the GBI, the attorney and part-time judge left his home at about 6:20 p.m. Monday, telling his family he was going to meet a client in Lamar County. He never returned. The following morning, family members contacted police.

“The Griffin Police Department began making inquiries as to Judge Johnston's whereabouts and contacted the GBI to assist at approximately 5:05 p.m. Shortly thereafter, the Spalding County Sheriff's Office contacted the Police Department and stated that Judge Johnston had been located in the vicinity of Jewel Drive and Pearl Circle in Spalding County,” the GBI spokesman said. “He was discovered by two EMC workers in his personal vehicle.”

In addition to his work as a city judge, Johnston was a partner with Johnston & Owen in Griffin, where he represented businesses, professionals, practice groups and financial institutions. His practice focused on general business litigation, banking and corporate litigation, contract disputes, formation of new business entities, commercial transactions, wills and trusts, and estate litigation.

According to his firm bio, he was born in Fort Benning, Georgia. He graduated from the University of Georgia in 1986 with a B.S. in microbiology and received his law degree from UGA Law in 1990. He first worked for Gardner, Willis, Sweat & Goldsmith in Albany. In 1994, he relocated to Griffin and established the law firm of Shepherd & Johnston. The firm changed its name to Johnston, Owen & Bullard in 2006.