Naim Stewart is on trial accused of robbing and beating a woman last September.
Samuel Booth was about to testify on Stewart's behalf when deputies say the woman recognized Booth as the never-caught second suspect in the attack.
Booth was promptly arrested in the courthouse and taken to the Gadsden County Jail. He's charged with armed robbery, aggravated battery, aggravated assault with a firearm and grand theft.
He'll go before a judge Saturday morning.