Five main accused, including two policemen, have been arrested in connection with the gang-rape and murder of two cousins in Katra village of Uttar Pradesh's Badaun district, police said on Saturday.
Constable Chhatrapal Yadav was arrested late on Friday night and Urvesh Yadav was detained in the wee hours on Saturday, superintendent of police AK Saxena told PTI.
The five accused named in the FIR, including constables Sarvesh Yadav, Chhatrapal and three brothers Pappu Yadav, Awadhesh Yadav and Urvesh Yadav have been arrested.
The FIR was registered against seven persons including two unnamed men after an outrage over the incident.
Katra Sadatganj police outpost in-charge Ram Vilas Yadav has been suspended and the two constables - Sarvesh and Chhatrapal - were sacked on Saturday, Saxena said.
While the two constables have been booked under Section 120B (criminal conspiracy) of the Indian Penal Code (IPC), the three brothers have been booked under Section 302 (murder) and 376 (rape).
The two girls, who were aged 14 and 15, went missing from their house on the night of May 27 and their bodies were found hanging from a mango tree in the village in Ushait area on May 28.
The postmortem report of the two girls' bodies confirmed that they were raped before being killed.
The family of the victims had also demanded a CBI probe, saying they had no faith in local police which was "hand in glove" with the accused.
The father of one of the girls had on Saturday called for transferring the case to the agency alleging that the role of police was "suspicious".
"Had the cops acted timely and did not showed laxity, lives of the girls would have been saved. They were hand in glove with the accused," father of one of the victims told PTI.
The Uttar Pradesh government has sanctioned financial assistance of Rs 5 lakh each to the family members of the victims while directing officials to provide security to them.
Chief minister Akhilesh Yadav has also ordered that suspects in the case be tried in special "fast track" courts.
On Friday, a video of the two teenagers' corpses hanging from a mango tree and swaying gently in a breeze drew relentless media attention and criticism in India and abroad.
Following an outrage over a spate of sex crimes against women in Uttar Pradesh, Union home minister Rajnath Singh has sought a report from the state government.