Defendant Lidia Shiryaeva explained that she had committed the quadruple murder because taking care of her four relatives had become too burdensome.
Shortly before the December 2021 killings, her husband had died from a head injury sustained in a car accident.
Her 23-year-old daughter had severe cerebral palsy.
Her grandchildren were aged three, five, and seven. Their mother was practically uninvolved in their upbringing and their father was almost always at work.
The defendant, her husband, her disabled brother, her son, and the victims lived together in the village of Aleksandrovka, Marxovsky District, Saratov Oblast.
Local media said that her husband's death had deeply affected her and had possibly driven her to commit the crime.
A medical examination had found Shiryaeva to be of sound mind, which her son reportedly still refuses to accept.
Shiryaeva only confessed to the crime last summer, recounting: "While everyone was distracted, I went outside and brought in a packet of poison.
"I knew that there was poison in my husband's car glove compartment. I added it to the soup, stirred it. Then I fed the grandchildren and my daughter with that soup."
In a statement obtained by Newsflash, the Investigative Committee of the Russian Federation said: "The evidence collected by the Investigative Committee of the Russian Federation in Saratov Oblast was deemed sufficient by the court to pass a sentence on a 50-year-old woman who was found guilty of committing the murder of two or more individuals, including minors, who were in a helpless state.
"The investigation and the court have established that on 11 December, 2021, at her place of residence in the village of Aleksandrovka, Marxovsky District of Saratov Oblast, the woman prepared food for her three grandchildren aged three, five, and seven, as well as her 23-year-old disabled daughter.
"Due to personal animosity, she added a poisonous substance to the food, resulting in the victims' deaths a few days later.
"Investigators seized numerous items at the scene of the incident and conducted forensic, sanitary-epidemiological, physicochemical, and other examinations. Additional investigative actions were carried out in August 2022, after which the woman confessed to the crime.
"The court's verdict imposed a punishment of 19 years of imprisonment with the serving of the sentence in a correctional colony of general regime, with one year of restricted freedom."