In this file photo, a police dog stands near the tree where two teenage girls were found hanging after they were gang raped in Katra village in the northern Indian state of Uttar Pradesh state. Picture: Rajeev Pal, File

New Delhi - Police have ordered a fresh autopsy on the bodies of two teenage cousins who were found hanging from a tree in northern India after being gang-raped, one of the victim's brothers said Wednesday.

The brutal rape and killing of the girls, aged 14 and 15, in an impoverished village in Uttar Pradesh state in May, sparked public outrage after the family complained of police apathy towards them because they were from a lower caste.

The 20-year-old brother of one of the girls Ä a cousin to the other victim Ä has been staging a protest in New Delhi for the last three days demanding justice in the case, which is being investigated by India's Central Bureau of Investigation (CBI).

The brother, who cannot be named for legal reasons, told AFP:

“My family was told Tuesday by the CBI that they will again conduct an autopsy on the bodies.

“Why wasn't it done right the first time?” he asked.

“The CBI is not investigating the case in the right manner.”

A CBI spokeswoman could not immediately confirm that the bodies were being re-examined.

But local media have reported that police planned to conduct a second autopsy because of shortcomings in the first procedure.

The young man, who said he lost his menial job at an automaker due to his absence from work following the killings, said he wants the case transferred out of Uttar Pradesh, alleging that political pressure is hampering the investigation.

Five men were arrested over the attack which took place when the cousins went into the fields to relieve themselves because their homes in Badaun district, like most in their village, lacked toilets.

Rights groups and political opponents have accused Uttar Pradesh's government of failing to tackle crimes against women.

India revised its laws on sex attacks in the wake of the December 2012 gang-rape of a student on a bus in New Delhi which triggered worldwide outrage, but they have done little to stem the tide of sex attacks.