A 20-year-old youth allegedly sexually assaulted a teenager at her house before killing her in the small hours of Sunday.

The incident occurred at Parvati under the jurisdiction of Ujjiarpur police station of the district.

The accused has been identified as Mohammad Irshad, a resident of Malti village under the jurisdiction of the same police station, about 100km northeast of the state capital.

According to sources, the youth is a neighbour of the 19-year-old victim and lived behind the girl’s house. The youth is associated with the bangle industry in Rajasthan and had come to the village around a fortnight ago. Sources added that the deceased hardly stayed at the village.

The victim’s widow mother, Madina Khatun, told police that the youth fled from her room when she shouted at him and made a noise. “Irshad sexually assaulted my daughter after covering her mouth with a towel but when I shouted at him, he killed her before running away away from there,” Khatun said.

Dalsing Sarai sub-divisional police officer Manish Kumar told The Telegraph: “On the written complaint of Madina Khatun, we have registered a case of murder and sexual assault against Mohammad Irshad under Ujjiarpur police station of the district on Sunday. We have sent the body for a post-mortem at the Sadar hospital in Samastipur.”

Manish said: “After post-mortem, the body would be handed over to the bereaved family. Whether she was sexually assaulted before murder or not can only be confirmed after the medical report arrives. We are waiting for it. The accused is absconding ever since the crime was committed. We are striving hard to nab the accused as soon as possible.”

He added: “Prima-facie, it seems the girl was raped before murder but only the medical report can confirm it. We are waiting for it. Our investigation is already on and it would be too early to arrive at any conclusion on who killed the victim and how?”

However, a source in the village said: “Police would investigate the case from different angles whether she was raped before murder or not. Things would be clear only after the medical report arrives. The report is expected to come by Tuesday. The family of the accused claimed the youth left home on Saturday evening but did not return yet.”