Speaking with the Russian Investigation Committee, the mother demonstrated to police how she had brutally killer her boy by shoving a ruler towards a child-like mannequin.
During the investigation Shishkina can be heard saying 'he went to open the entrance door, like "Mummy, we need to go home".
'I didn't go. He decided to open the door, did not listen to me. I grabbed the knife,' she said.
The woman admitted to stabbing him 'two or three times in his side.'
Shishkina also has a five-year-old son who was not with her at the time of the attack.
He has since been taken into care while his mother has been detained.
It's reported that the woman was being supervised by social services, which has sparked outrage from people across the nation.
Senior regional politician Roman Titov has questioned why the children were not taken into care earlier.
'What else needs to happen for the responsibly federal agencies to recognise we are going the wrong way?' he asked.