"Despite having a broken leg and being on crutches, the woman waited until her son-in-law had fallen asleep and hit him several times around the head with the blunt side of an axe," regional investigators said in a statement.
The man was able to put a stop the attack, investigators said.
They did not give any information on the motive for the crime or the victim's condition.
The incident took place in February in Mariinsk, a small town in Russia's West Siberian Kemerovo region.
Kareena Kapoor Khan looks in fab shape after weight loss! See photos
Mumbai food: 9 dishes to try during 9 days of Navratri
Photos: Hrithik Roshan, Nidhhi Agerwal and Adah Sharma walk the ramp
Photos: Shah Rukh Khan spotted with new set of wheels
Photos: Kareena Kapoor Khan, Kangana Ranaut at the Mumbai airport