A woman who served 43 years for a murder she did not commit has been released after her conviction was overturned.

Sandra Hemme was 20 years old when she was found guilty of stabbing to death library worker Patricia Jeschke from St Joseph, Missouri, in November 1980. She was given a life sentence.

There was no evidence that linked her to the crime other than a confession she gave under heavy sedation in a psychiatric hospital, a review into her case found.

Now 64, she is believed to have served the longest known wrongful conviction of a woman in US history according to her representatives.