An 11-year-old girl and her 14-year-old boyfriend have been seized by police in Brazil for stabbing her mother to death and trying to kill her stepfather.

The girl apparently lured her 38-year-old mum to her room where she and her boyfriend ambushed her armed with knives.

Police in the coastal city of Vila Velha, in the state of Espirito Santo, said she managed to escape but then died of her injuries on 27th October.

Shocked investigators later found a chilling entry in the girl’s diary for the day before the bloodbath saying: “We’ll even kill my parents to be together.”

After killing her mother, the girl and her boyfriend lay in wait at the family home for her stepfather armed with a baseball bat and a knife, according to local media.

The stepfather told local media: “I called ‘love’ and no one answered, then I saw blood on the floor. The first blow was very strong, I almost fell. If I had fallen, I’m sure they would have killed me.”

The 32-year-old stepfather fought back and survived and the two minors were taken into custody after police arrived on the scene.

The young girl reportedly told police that she had been planning her mother’s murder with her boyfriend for a week.

Both suspects reportedly admitted to having stabbed the girl’s mother and attacked her stepfather.

But despite her shocking confession, the girl cannot be prosecuted as she is under the age of 12 and cannot be held criminally liable under Brazilian law.

The police said in a statement: “The teenager stated that they had been dating for two and a half months and that the victim’s death had been planned for a week.

“The motivation, according to the teenager, is related to complaints that the girl made regarding family life.”

One police officer told local media that it was very strange interviewing the young girl because she very much appeared to be childlike and innocent.

The investigation is ongoing.