A 10-year-old mentally challenged boy allegedly beat his one-year-old sister to death with bricks and sticks in a village in Uttar Pradesh's Bahraich district, police said on Friday.

The incident was reported to the police at 7 pm on Thursday evening by the children's grandfather.

Ramanand Mishra from Rehua Mansoor village told police that his grandson who is mentally challenged, has seriously injured his younger sister while playing inside the house.

He hit her on the face with a stick and a piece of brick, due to which she died on the spot, Mishra said.

Circle Officer (CO) DK Srivastava told reporters that Ramgaon police station has registered a case under relevant sections and sent the body for post-mortem. Police are investigating the matter, he said.

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