The Kurukshetra Police on Saturday added a charge under the Prevention of Atrocities against SC/ST Act in the case of rape and murder of a 16-year-old girl.
The teenage victim was kidnapped on Wednesday night by unidentified youngsters near Kurukshetra's Jindal chowk. Her body was recovered from a canal in Karnal's district Sandholi village on Thursday.
The police are yet to make any breakthrough in the case.
The police said a person was being questioned in the case, but refused to give further details.
On Friday, hundreds of residents had protested against the alleged laxity of the police in cracking the kidnapping case, and blocked national highway I for more than six hours.
The victim's family members alleged that when they went to the police station to register a complaint, the officer on duty expressed his inability to do anything and told them to come in the morning.
Earlier on Saturday, Raj Kumar Virka, vice-chairman of the national commission for scheduled castes and backward classes, slammed the police for not registering any charges under the SC/ST act.
"Cases of atrocities against people from schedule castes and backward castes are on the rise in Haryana," he said.
He said the commission was drafting a list of officers failing in their duty to protect the life and dignity of people from lower castes.
Virka urged the state government to give a compensation of Rs 12 lakh to the family of the victim.