A Class X student of a school in a southern Calcutta pocket has alleged that she was repeatedly raped by a private tutor who would threaten to shoot her by showing a gun if she protested.

Police said they have recovered a few cartridges from the house of the accused — Rajib Chakraborty — but the gun was yet to be found.

The 48-year-old was arrested on Monday night based on a complaint lodged by the student in her teens.

He has been charged with sections of the Protection of Children from Sexual Offences (Pocso) Act.

According to the complaint, the tutor repeatedly subjected the girl to sexual assault when he would visit her home for giving tuition.

The police said Chakraborty had been running a coaching centre over the past few years. He taught mathematics, physics, chemistry and geography to students of classes V to XII.

“The student said the teacher would visit her home to teach her, though on certain days she would turn up at the coaching centre, too, to attend classes,” said an officer of the police station where the complaint has been lodged.

“The student has said she had been subjected to torture multiple times when she was alone at home. The tutor would force her at gunpoint to do his bidding.”

The girl’s parents have told the police that they were unaware of the incidents till their daughter confided in them on Monday, prompting them to seek police help.

A number of incidents of teachers allegedly sexually harassing their students at school or coaching centre were reported from across the city in recent past.

In December 2017, two teachers of a girls’ school in south Calcutta were arrested on the charge of sexually harassing a four-year-old student on the school premises. The police later included the gang-rape charge against the teachers.

Again in December 2017, an employee of a school on the southern fringe had been accused of sexually harassing a three-year-old student on the campus.

Custody trial had begun in both cases and the accused are yet to get bail.

“Guardians must monitor the behaviour of their children and encourage them to speak out if there is any unusual change in their behaviour. The moment anything suspicious is spotted, it should be reported to the police,” a senior officer said.

An officer involved in the investigation into the complaint lodged by the Class X student said though the gun had not been recovered till Monday, the recovery of cartridges had given credence to the statement of the teenager.

Soon after the student and her parents went to the police station on Monday evening to report the matter, a team of officers left for the coaching centre and detained the accused for interrogation.

He was later arrested at the police station.

“We raided his home based on his statements and seized the bullets,” the officer said.

A relative of the accused said he had a strained relationship with his wife.

Chakraborty’s elderly parents went to the police station and told officers that their son was a victim of conspiracy.

“They (the accused person’s parents) said their son was innocent,” an officer said.

Residents of the area where the coaching centre is located said many students would turn up at the coaching centre and park their cycles on the road.