A dead kitten was found near a house in the village of Krasnaya Sopka in Krasnoyarsk Krai.
Four children died in this house days earlier from poisoning by an unknown substance.
TASS reported this with reference to the Russian Investigative Committee.
Investigators said that the kitten's body was sent for examination.
This will help to find out whether the animal's death is related to poisoning and the death of children.
The parents of the deceased children were discharged from the hospital.
The mother is nine months pregnant. Doctors have said that the fetus is not in danger.
The uncle of the deceased children also said that before the strategy the house was treated with dichlorvos.
In his opinion, this could have been one of the causes of the tragedy.
The investigation is considering two main versions of the children's deaths: poisoning by an unknown substance in food and poisoning by aerosol vapors.