The body of two-year boy was found on Friday in an apartment in western Moscow, a police source said.
"A boy's body with numerous stab wounds was found in a bath filled with water in an apartment block," the source said.
An investigation is underway.
Russia has an appalling record on child abuse, with around 2,000 children a year dying at the hands of adults, in many cases their parents or other family members.
There have been a number of public awareness campaigns to persuade parents to reject violence as a childrearing method.
Moscow, May 20 (RIA Novosti)
