© Getty Police have arrested a 12-year-old girl for allegedly murdering her adoptive mother with the help of her boyfriend in Fatehpur on Sunday.

The woman was reportedly averse to the girl’s relationship with the Class 9 student, two years her senior in school.

Fatehpur superintendent of police Sriparna Ganguly said the duo has been booked for murder, and sent to a juvenile home.

“The girl misread the punishment she received from the woman, who adopted her when she was just three months old, as a sign that she did not love her,” said Ganguly.

Police said the girl also destroyed two cellphones to cover up the crime, and then told neighbours that her 45-year-old adoptive mother was too unwell to take their calls.

The two would have got away with the alleged crime, if not for an alert neighbour who alerted the police.

Kotwali station house officer Sunil Singh said the girl invited her boyfriend to their house at Turab Ali ka Purva in Fatehpur sadar on Sunday evening, infuriating her adoptive mother.

She reportedly slapped her and told the boy to leave.

However, she called the boy to their residence again around midnight. That night, while the woman was sleeping, they allegedly strangled her and locked the body in another room.

“After committing the crime, the girl left the house with the boy and spent the night with him elsewhere.

The next morning, after the duo had breakfast at a restaurant, they destroyed the cellphones,” said Singh.

Around noon the next day, the girl returned to the house and approached a neighbour.

She told him that her adoptive mother was lying motionless in the house, and obliquely blamed her condition on an ailment for which she had been consulting a doctor in Kanpur.

Upon discovering that the woman was dead, neighbours informed her husband in Mumbai.

Everybody in the locality believed her story, and were in the process of preparing the body for burial when a suspicious neighbour informed the police.

The girl reportedly broke down under questioning on Tuesday noon, and confessed to her involvement in the murder.

The boy was later picked up by the police.