A youth was killed and his father injured as they confronted a three-member gang who gangraped his sister in Fatehpur Chaurasi area of the district, a senior officer said on Tuesday.
Additional Superintendent of Police Sarvanand Singh Yadav said the 13-year-old girl was raped by Mahendra Kumar, Nand Kishore and Awadhesh Kumar last night.
When the girl's father and brother confronted the culprits they were thrashed brutally by them.
The brother later died on way to hospital and her father sustained injuries in the attack, he said.
The ASP said a case of rape and murder has been lodged against the trio and two of them -- Mahendra and Nand Kishore -- have been arrested.
A medical examination of the victim was being conducted, he added.