KNOXVILLE, Ga. -- The metro Atlanta man known as the 'Grandpa Bandit' pleaded guilty to four counts of bank robbery Tuesday before U.S. District Court Judge Tom Varlan in Knoxville, Tenn.

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Investigators said Bobby Joe Phillips, 65, kicked off his crime spree by robbing the First Georgia Community Bank in Covington in September. Authorities say he went on to rob two banks in Knoxville four separate times, the SunTrust Bank in Suwanee and the Security Bank in Warner Robins.

Police arrested Phillips at a hotel in Perry, in November.

He faces a maximum sentence of 20 years on each count, and sentencing is set for July 31.

Covington officials plan to prosecute Phillips for the bank robbery there.

Phillips said he began robbing the banks after he was fired from his job as a cashier at a Kroger store in Covington and he needed money. He pulled his first hold-up the day after he was let go.