Authorities in Japan are facing demands to do more to protect children from abusive parents following the death of a 10-year-old girl who was returned to the care of her father despite evidence that he had been violent towards her.

Mia Kurihara was found dead in the bathroom of her home in Chiba, near Tokyo, in January, just over year after telling teachers that her father, Yuichiro Kurihara, regularly beat and bullied her.

Her body was found with bruises and scratches, and she appeared to have been repeatedly doused with cold water. Kurihara was arrested the following day on suspicion of causing bodily harm, and her mother, Nagisa, was arrested this week in connection with their daughter’s death. An autopsy failed to establish why Mia had died.

The case has attracted huge media attention and prompted criticism of Japanese authorities amid a dramatic rise in the number of abuse cases.

Police reported the suspected abuse of a record 80,104 children last year, according to government figures released on Thursday, up almost 25% from the previous year. Experts attributed the rise to growing public awareness of the issue in the wake of several high-profile cases.

Japanese welfare officials and police have traditionally been reluctant to investigate allegations of child abuse and domestic violence. Social workers complain they are under-staffed and lack the powers to intervene to protect children when confronted with uncooperative parents.

Mia’s death, however, prompted experts to call for drastic changes in the way authorities investigate child abuse, including closer cooperation between the police, teachers and welfare authorities.

“People must recognise that child abuse is a very serious matter that cannot be dealt with by one organisation alone,” Keiji Goto, a lawyer, told public broadcaster NHK.

The prime minister, Shinzo Abe, vowed to eradicate child abuse in response to Mia’s “heart-wrenching” death. “We failed to respond to the call for help that she had courageously sent out,” he told MPs this week. “As a government, we take that seriously.”

The widespread revulsion that greeted the death last March of Yua Funato, a 5-year-old girl who was starved to death by her mother and stepfather, prompted the government to introduce emergency measures, including increasing the number of case workers and granting child welfare officials powers to remove at-risk children from the care of their parents.

Funato had begged her parents to stop mistreating her, pleading with them to “forgive me” in a notebook found after her death.

Newspapers joined calls for the government to take urgent action. Mia’s case, the Japan Times said in an editorial, “underlines once again that similarly tragic consequences of child abuse will likely be repeated unless all the relevant parties take all warning signs of child abuse seriously and respond in a manner that places the utmost priority on the safety of children”.

The primary school pupil had revealed her father’s abusive behaviour in a questionnaire at school in late 2017. “My father is violent towards me,” she wrote, after being assured that her answers would remain confidential. “He wakes me up in the middle of the night and kicks and beats me. Teacher, is there anything you can do about this?”

Under pressure from her “aggressive” father, local board of education gave him a copy of Mia’s questionnaire – a decision experts said could have led him to behave more violently towards her.

Mia was placed in protective custody but was sent back to her parents a month later after officials received assurances that her mother would play a bigger role in her upbringing, Japanese media said.

Her father is also suspected of forcing her to write a note saying she had lied about his behaviour and wanted to move back with her parents.

According to Japanese media, education officials did not make follow-up visits to Mia’s home to check on her welfare, even after a long absence from school.