SEOUL - She was a cheerful baby bouncing with energy, her chubby cheeks earning her the nickname "Little Peach".

Although given up at birth for adoption, the little girl named Jung-in blossomed under the loving care of foster parents.

When she was seven months old, a so-called "perfect family" came along to adopt her.

The couple in their 30s were known to be devout Christians who wanted a younger sibling for their four-year-old daughter.

The husband, surnamed Ahn, worked in a broadcasting company, while the wife, surnamed Jang, was an interpreter who had studied overseas.

Both of them had helped Korean adoptees before and they even went on a television show with both children, saying "adoption is not a shame but something to be celebrated".

What was supposed to be the beginning of a happy life for Jung-in, however, turned into a nightmare.

She was just 16 months old when she died on Oct 13 last year, her pancreas ruptured and her stomach bloated with blood, after months of extensive abuse by her adoptive mother, who has been arrested and will go on trial on Wednesday.

The brutality of Jung-in's death caused a national uproar, with celebrities including BTS member Jimin joining a #SorryJungin campaign on social media to mourn and vent against child abuse.

Actress Han Hye-jin wrote on Instagram that she was so upset that she could not sleep. "What was done to Jung-in was cruel, vicious and horrific. How could they do this?" she posted.

Child abuse has long been a problem in South Korea, where abusive parents consider their children as their "property", and feel they can do anything to them, including being violent and neglectful. If questioned, they are known to retort "this is my way of raising my child".

Official data showed that there were 41,389 reported cases of child abuse in 2019 - up from 29,671 in 2016. Experts believe there could be a lot more unreported incidents, which are considered family matters and not police cases.

A major case seems to emerge every few years, shocking the nation and triggering protests and demands for stiffer penalties for child abuse.

Two gaming addicts were arrested in 2010 for neglecting their three-month-old baby and leaving her to starve to death, while they were out playing online games in Internet cafes.

A man was found to have beaten his seven-year-old son to death and dismembered his body for disposal. Some parts were flushed down the toilet, some thrown in the trash, and some still stored in the home freezer when the truth came to light three years later in 2015.

Activists have lambasted the government's inability to protect children from violence despite repeated promises to do so, noting that Bills related to child abuse are still languishing in Parliament.

And now, there is the sad case of Jung-in, which has sparked calls for stricter screening for adoption and more proactive police reaction to reports of suspected abuse.

It turned out that three separate reports had been made about Jung-in, including one by a paediatrician who had examined her bruises, but the police did not investigate further.

When a childcare worker first reported suspected abuse to the police, the parents claimed they had probably massaged the girl too hard, resulting in bruising.

It was only after Jung-in's death that the police found 800 abuse videos on her adoptive mother's phone. She will be charged over involuntary manslaughter by child abuse, and her husband, child abuse and negligence.

Jung-in's case drew renewed public attention last week, after the case was featured in SBS TV station's investigative programme Unanswered Questions on Jan 2.

Viewers were horrified to see a simulation of the amount of brute force needed to rupture Jung-in's pancreas. Taekwondo kicks would not be enough, according to the show. But it could happen if Jung-in's adoptive mum were to jump off a sofa and land on her body.

Speculation had also emerged that the family adopted Jung-in only as a "gift" for their biological daughter, and that they pushed for adoption in order to get a bigger housing loan that is offered to families with more than one child.

There are now calls for the mother to be tried for murder instead. The Korean Women Lawyers Association (KWLA) issued a statement last Monday saying that the evidence gathered so far points to murder.

The association also urged the government to allocate more resources and manpower to investigating child abuse cases, noting that 28 children died of abuse at home in 2018 alone.

South Korean President Moon Jae-in has since ordered agencies to make all efforts to better protect young adoptees, while police chief Kim Chang-yong issued an apology for the police's "botched initial response and inadequate investigation", and promised to overhaul the way they respond to child abuse reports.

But the KWLA said that without any substantial action, this will just be an empty promise.

• Additional reporting by Jane Lee