The 14-year-old, who is suspected of carrying out the murder with her boyfriend, attempted to conceal her mother’s death by using insecticides and air fresheners to mask odors, according to police in the town of La Molina, east of Lima.
Her father, an octogenarian suffering from Alzheimer’s, had continued to live in the house unaware that the killing had taken place.
Commander Rafael Moron said the girl told officers that her 16-year-old boyfriend had committed the killing, attacking her 63-year-old mother with a dumb-bell after she had reacted angrily to finding the couple alone in a locked room of the family home.
However, her boyfriend, who surrendered to authorities on Tuesday, has denied the killing, insisting the girl, identified only as Stephanie, was responsible.
Police said after the killing on Jan. 11, the dead woman’s daughter continued her life as normal, entertaining friends at home and regularly posting updates to her Facebook page.
Under Peruvian law, minors who commit murder are not tried as adults, but instead face treatment at a secure mental health facility for a period not exceeding six years.
The case has shocked the public in Peru, reviving memories of a similar crime last November when a 22-year-old killed his mother with the help of a partner, also in La Molina. Both accuse the other of carrying out the murder.