A police officer used "unreasonable" force when she Tasered a race relations adviser, a misconduct hearing has been told.
Acting Sgt Claire Boddie pulled the trigger in January last year, in Easton, Bristol, after mistaking Judah Adunbi for a suspect.
An Avon and Somerset Police misconduct hearing heard Mr Adunbi had been mistaken for a suspect by the officer.
She denies a series of misconduct charges brought by the force.
A hearing at its headquarters in Portishead was told Mr Adunbi, 65, had been walking his dog at about 09:10 GMT on January 14 last year.
PC Boddie was on uniformed duty with colleague PC Darren Weston and mistook Mr Adunbi for wanted man Royston McCalla.
He refused to give his name to officers, accusing them of being racists.
He then opened a gate to a back alley and forced it closed after being told he was going to be handcuffed.
In her defence, PC Boddie said the force she used against Mr Adunbi was lawful, claiming that he posed a threat as he had keys in his hand and was "using violence to escape".
She told the hearing that as Mr Adunbi came back out into the street he appeared to strike her colleague with his left hand.
Ms Boddie said "red dotting" Mr Adunbi minutes earlier with the Taser had no effect in calming him, adding he adopted a "fighting stance" when told he would be handcuffed.
She said she fired at his chest, adding: "It was regrettable a barb hit him in the face. You aim for the belt."
Ms Boddie is accused of firing the Taser as Mr Adunbi was walking away, not giving a warning she was going to fire, and firing the Taser in a way which caused a probe hit him in the chin.
The Avon and Somerset force said her alleged actions "constituted a breach of the standards of professional behaviour for the use of force".
"The alleged conduct taken individually or together, amounts to gross misconduct," it added.
The hearing continues.
In May, PC Boddie was found not guilty of assault by beating following a trial in Salisbury.