According to investigators, the 38-year-old suspect remained with his two-year-old son and daughter while his 26-year-old wife went to the store.
The UK said that the man took the carrier with his daughter and climbed into the attic, where he stabbed her in the neck area with a knife.
In connection with the incident, a criminal case was initiated under Part 2 of Art. 105 of the Criminal Code of Russia "Murder of a minor."
“Currently, the suspect has been detained, investigative actions are being carried out with him,” the UK said.
Earlier in Bashkiria, on the suspicion of murder, the mother of a child who allegedly disappeared from the cradle was detained.