Occasionally people are convicted of manslaughter and not murder, or found to have killed in self-defense.
In 2008, Israel even passed a law justifying some killings and exonerated a farmer in the south of the country who shot an intruder who had come to steal his property.
Not every murderer receives a life sentence. The law allows for a lesser sentence if the accused was under severe emotional stress due to prolonged abuse by his victim.
Dalal Da'ud was convicted for the murder of her husband in 2002. She was sentenced to 30 years in prison. A decade passed before she first revealed the full horrific story of her abusive marriage.
She had turned to the police no less than 26 times, but her complaints were never followed up on and her husband was never stopped.
The hospital had kept records of her injuries, stitches, fractures, beatings while pregnant and psychiatric evaluations of her morbid fear of her husband, but did nothing beyond that.
The Sharia Muslim court she turned to begging for a divorce sent her home to "patch things up" with her tormentor.
Even social services who were aware that she was a so-called battered wife - it was common knowledge in her community - did nothing. Nobody offered help and her horror continued until one day she snapped, and committed murder.
The information about Da'ud's marriage was not presented in her first trial and when finally revealed did not facilitate a new one, but in 2014 her sentence was commuted to 25 years and in 2017, President Reuven Rivlin decided she should be allowed to request early release from prison.
Two more years have gone by but Da'ud - who is now 49 years old - will on Wednesday appear at the Ramle Magistrate Court for a session of the parole board, to ask to be set free.
The prosecution and prison authorities do not think she should be released. She needs more rehabilitation, they say. And the law is the law.
But Dalal was severely abused over a long period of time. If murder has mitigating circumstances then given her suffering, the violence she endured, the rape and the assault on her body, her mind and her life, is this not such a case?
Murder cannot be justified, but the abuse Dala Da'ud endured cries out a simple truth: This woman was a prisoner long before she began serving her sentence. She was imprisoned by her husband and by the legal authorities and social services that had failed her. She was a desperate woman who committed a desperate crime, doing the only thing she could to free herself from the monstrous life she was trapped in.
She has already paid the price with 17 years in prison, and if there is any justice in this world, then on Wednesday she will finally be free.