A CORONIAL inquest into the death of Narrabri woman Penny Hill twenty one years ago has begun at Tamworth Court House this morning.

When school teacher Susan Brown came to the aid of an unconscious Penny Hill on the side of a road in Coolah in 1991, she knew she had witnessed the "work of a bad man."

Ms Brown was the second person to give evidence on the opening day of the inquest into Ms Hill's brutal murder.

The court heard that Ms Brown was driving on Cassilis Rd where she found Ms Hill badly beaten and clinging to life near the gate of a property on Monday, July 8.

Near her hand was the cord of an electric kettle which medical evidence to the court suggested the cord was consistent to the injuries found on Ms Hill's neck.

She died in John Hunter Hospital two weeks later.

Ms Brown recorded her observations of her discovery in a notebook entry which was tendered to the court yesterday.

On delivering her evidence, Ms Brown, a science teacher, told the court she initially thought Ms Hill had fallen off a horse but her un-dishevelled appearance and clean ugg-boots she was wearing were not consistent with sticky black soil where she was dumped on the roadside.

"I don't know what's happened here, nothing adds up," was what Ms Brown said to the first police officer to arrive at the scene.

The inquest is expected to run for at least four days at the Tamworth Court House and is being led by Deputy State Coroner Sharon Freund .

As many as 20 witnesses are expected to give evidence including Barbara and Colin Baigent who were Ms Hill's employers at the Black Stump Motel at the time of her death.