Bodies of rape girls to be exhumed
Investigators plan to exhume the bodies of two teenage girls raped and killed by attackers who hanged their bodies from a tree in northern India six weeks ago.
The families of the girls demanded the killings be investigated by the federal agency to ensure impartiality.
Five men arrested in connection with the deaths and the girls' family members have undergone lie-detector tests in the past week.
India has a long history of tolerance of sexual violence, but the attack on the girls has caused outrage across the nation.
The CBI sought the permission of the girls' families to conduct a second post-mortem examination.
State investigators conducted one soon after the bodies were found but it "left many questions unanswered", the police official said.
The public anger over the case was reminiscent of the reaction to the December 2012 fatal gang rape of a 23-year-old woman aboard a moving bus in New Delhi, India's capital.
After that attack, the federal government changed India's sex crime laws, doubling prison terms for rapists to 20 years and criminalising voyeurism, stalking and the trafficking of women.
The law also makes it a crime for officers to refuse to open cases when complaints are made.