By Jon Donnison

BBC News, Washington



Please turn on JavaScript. Media requires JavaScript to play. Advertisement

A 72-year-old great-grandmother in Texas has threatened to sue police after an officer "tased" her with an electronic stun gun.

Kathryn Winkfein was pulled over for speeding while doing her weekly shopping in Austin, Texas.

The officer shocked her with the taser gun after she resisted arrest and became argumentative.

CCTV footage showed her screaming with pain on the ground but police say that she was not seriously injured.

Mrs Winkfein was stopped by a police officer for speeding in her white pick-up truck.

Grainy police video footage shows the officer shove her and point the taser gun at her as she refuses to go quietly.

She dares the officer to shoot her, he opens fire.

As Mrs Winkfein writhes on the ground, the officer threatens to shoot again.

Taser guns fire 50,000 volts. They are widely used by police in the United States and are categorised as non-lethal weapons.