Mayor Megan Barry announced her resignation at around 10 a.m. this morning, after pleading guilty to theft of property over $10,000 in court today.
Her plea deal requires Barry to serve three years of probation and repay the city $11,000.
She is being investigated by a Metro Council special committee and the Tennessee Bureau of Investigation for potential misuse of funds.
In late February, the TBI released reportedly found a nude and partially nude photo of a woman on the Forrest's phone.The agency said it proves Barry was having an affair while he was on duty.
The photos were discovered in Forrest's work email, the filings state. Forrest, who is also married, retired January 17 after reports of the relationship emerged.
The Democrat mayor is the first from Nashville to leave office before the end of their term in almost a century, per The Tennessean.
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He was sacked from the Trump campaign in July 2015 , after it emerged he had posted racist comments on Facebook years ago. While on set with Erin Burnett on Monday evening, the CNN host openly accused Nunberg of being intoxicated while on air.
The resignation means that Vice Mayor David Briley will become acting mayor.
Metro Nashville Police records show Forrest's overtime more than doubled in the budget year after Barry was elected in September 2015. He headed her security detail at City Hall.
The last Nashville mayor to leave office before their term expired was in 1923 - decades before the formation of Metro government - when Mayor Felix Z. Wilson was kicked out of office by the Nashville City Council.
"We had an affair, and it was wrong, and we shouldn't have done it", Barry said.
The revelation comes just several weeks after Barry confirmed an affair with a now retired body guard named Rob Forrest. According to the newspaper, Forrest accompanied Barry on trips to Paris, Washington, New York, Denver, Oakland and other cities in the past year. It was filed in the Criminal Court Clerk's office, and Barry's attorney said he provided the pass code to the mayor's personal cellphone to investigators days later. She was the point person for a $5.4 billion transit plan that Nashville voters will consider in a citywide referendum in May. After that change, Anderson - who ultimately was Forrest's supervisor - did not receive automatic notice of any travel requests for Forrest or other members of the mayor's security detail, although his signature was automatically generated by the computer system as approving the travel.