Tinsukia | A 12-year-old girl was raped and killed in Assam's Tinsukia district, police said on Thursday.

The accused, who fled to Arunachal Pradesh, was later critically injured in police firing when he tried to escape from custody after his arrest from the neighbouring state, a senior officer claimed.

The rape and murder of the minor, which took place in Margherita, led to a public outcry with thousands hitting the streets in the town with a demand to arrest the culprit immediately.

Tinsukia Superintendent of Police Gaurav Abhijit Dilip said the incident took place on Tuesday and the body of the victim was recovered from a septic tank on Wednesday.

"The families of the victim and the culprit are known to each other. The mother of the girl and the wife of the rapist are maids. On Tuesday, both women went to work together and kept the girl at the culprit's house," he added.

When they returned from work, the girl was not there and the accused claimed that she had gone home, the SP said.

"After her mother could not find her at home also, she filed an FIR and police started an investigation. The accused had fled by then. We picked up his wife and she confessed during interrogation about her husband's crime," he added.

The SP said as per information of the wife, the police team recovered the body of the victim from the septic tank of the accused's house.

"We have formed a Special Investigation Team (SIT) and I am heading it. We have formed five teams, which have launched search operations along the Assam-Arunachal Pradesh border to nab the culprit," he added.

Later on Thursday evening, the accused was arrested at Deomali town in Tirap district of Arunachal Pradesh, Dilip said.

"When a police team was bringing him back to Tinsukia, he tried to escape from custody. Police asked him to stop, but he did not. With no option left, police fired at him," he added.

He was grievously injured and immediately taken to a nearby hospital, Dilip told PTI.

Earlier during the day, people of Margherita town came out on the streets on Thursday and protested against the crime. They blocked the main road of the town and burnt tyres on it.

The police, however, did not use any force to disperse the crowd, which was high on emotion after the cruel death of the minor.