Roderick Fleming, who's 44, pleaded guilty to the charge of aggravated assault.
In December, Fleming entered the Stripes convenience store in the one-thousand block of Holliday.
He pointed a knife at the store clerk, took money from the store's register, and ran.
An officer saw Fleming several blocks down the road from the store, but he fled from officers.
Police say that hours later, he approached officers and was arrested.
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