Madhu, a resident of Dupty Ganj, was staying with her three sons-- Abhishek (9), Guddu (7) and Suraj (5) at her father's residence since her divorce fours years back.
Her brother reportedly found the children lying in an inactive condition yesterday morning, when he entered their room to prepare for school.
The family immediately called the doctor, who declared them dead. Later the police was called and bodies were sent for post-mortem.
"The cause of death could not be ascertained as family members are in a state of shock and not in a position to give details of the death," Inspector, Civil Lines, Sresh Chand said.