A mob laid siege to Jakkanpur police station for two hours on Sunday, asking the police to hand over the alleged killer of a seven-year-old girl to them for instant justice.

Prime suspect Saurabh Kumar Jha was arrested from Kishanganj on Friday night after seven-year-old girl Prerna’s body was found a day ago from under the water tank of a building he lived in.

Agitated by Prerna’s murder, Indira Nagar residents blocked the road in front of the police station, burnt tyres and paralysed movement of vehicles on the Patna Junction-Mithapur bus stand road. The blockade threw traffic on the southern end of Patna Junction out of gear. The mob turned violent and smashed the windscreens of several private vehicles when the police used force to disperse them. The situation was bought under control after senior police officials intervened and promised stern action against the culprit.

Patna senior superintendent of police (SSP) Manu Maharaj said Saurabh, who was brought to Patna from Kishanganj on Sunday, would be produced in court after interrogation. A forensic team picked up fingerprints and blood samples from the scene of crime. Saurabh has confessed to his involvement in the crime, he said.

Maharaj added that the case would be put on speedy trial on the basis of forensic evidence. “We have enough evidence to get the offender prosecuted in the court of law,” he said, adding that the members of the SIT, assigned to crack the case, would be suitably rewarded.

Initially a missing case was lodged with the Jakkanpur police station after the family failed to trace the girl. The next day her body was recovered from under the water tank. A special team was constituted to arrest Saurabh, who was absconding since the incident. Acting on a tip-off, the team raided a house in Paschimpali locality of Kishanganj and arrested him. During interrogation, Saurabh said he strangulated Prerna after she threatened to tell her aunt about his attempt to outrage her modesty. Saurabh later hid the girl’s body under the water tank of the four-storeyed building and fled.

SSP Maharaj said Saurabh, a native of Supaul, is a student of Class VII. He was staying on rent in the same building where Prerna had come to meet her aunt Vimla Devi and her husband Bindeshwari Pandit.