System Of A Down frontman Serj Tankian has expressed support for the three Russia-based sisters who killed their father after he "raped and abused them throughout many years."

The teenage sisters, whose father is Armenian, are to be charged with murder in Russia.

The case saw investigators testify the sisters were repeatedly tortured, sexually abused and raped.

"A very tragic case in the Russian courts is further unveiling the failure of that system towards victims of domestic abuse and pitting left against right within the country. It is a complex case with multiple victims besides the deceased," Tankian said.

"It’s a prime example of how years of violence against women and children with no justice and prosecution can cause a violent revengeful attack. The courts need to show leniency on these girls given the systemic failure."

The father, 57-year-old Mikhail Khachaturyan, was stabbed with a hunting knife.

The sisters - Krestina, 19, Angelina, 18 and Maria, 17 - were earlier released from custody on a judge’s order.

Lawyers had pressed for the murder allegations to be dropped against all the sisters or mitigated by re-categorizing the case as causing death by “self defense”.