At nine months old she was adopted by Alfonso Basterra Camporro (born 1964) and María del Rosario Porto Ortega (1969–2020), an affluent Spanish couple from Santiago de Compostela, Galicia.

[10][15] On 26 June, Rosario was admitted to the Neurology Department of the Hospital Clínico de Santiago due to a worsening of her illness, with dizziness, instability when walking and drooping of an eyelid.

After being made aware of the video Porto changed her story, this time saying that Asunta had briefly come with her to the country house, but that she quickly took her back to Santiago because the child had wanted to do homework.

Porto claimed she then returned to the country house in Teo to retrieve her purse, then went to a gas station but did not fill her tank because she realized she did not have her discount card.

In June 2014, Examining Judge Vázquez Taín put an end to the pre-trial investigation of the case, giving way to the process of opening trial.

[36] The investigation into Asunta's death was named Operación Nenúfar ("Operation Water Lily") by detectives, who noted that in the moonlight, the girl's body in her white shirt appeared to be floating above the ground like a flower.

[37] The parents' activities could be reconstructed in the hours leading up to their daughter's disappearance and death, thanks to testimonies, surveillance cameras, and records from phones and digital devices:[38] During the examination of the body, the forensic experts did not take a rectal temperature for fear of destroying or contaminating evidence, as sexual assault was suspected.

[47][17][page needed] In a first version of the events, Rosario Porto had declared that she left Asunta at around 7:00 pm at her home in Santiago de Compostela, and that when she returned a couple of hours later, the girl was no longer there.

On Tuesday, 24 September, after the cremation of her daughter's body, Rosario was arrested and charged due to the inconsistencies, contradictions and changes of version in her statements.

[54] An analysis of Asunta's hair revealed that she had consumed high doses of lorazepam three months before her death, which is associated with the testimonies of dizziness and drowsiness provided by the teachers at the music academy.

[59][60] In early October, the Civil Guard's central crime laboratory identified the genetic profile of a man, a young Colombian resident in Madrid, when testing two samples of fabric cut from Asunta's T-shirt.

[62] These phrases do not appear in the official police transcript nor are they heard in any other part of the conversations that were not transcribed, yet they were accepted and repeated for years, before and after the trial, by almost all the Spanish media, including public television.

Rosario Porto's lawyer considered the photographs "normal and irrelevant" and claimed that the Civil Guard had been in possession of Asunta's mobile phone for nine months but had allowed them to be leaked to the press at the right time to create a hostile atmosphere towards the parents and try to influence the jury's opinion.

Following the jury's verdict and the condemnatory sentence, Rosario Porto's lawyer, José Luis Gutiérrez Aranguren, expressed his opinion that the jury was contaminated by the media[77] and that he would state this in the appeals that he was going to present before the High Court of Justice of Galicia and the Spanish Supreme Court:"In the case at hand, the impact of the mass media in the formation of a preference for the accusatory thesis in public opinion is ostensible.

"[78]At the end of the trial, which lasted more than four weeks and for which 135 witnesses were called,[79] and after four days of deliberation, the jury returned a guilty verdict for both parents that resolved some of the main issues in the case, but also left doubts.

[82] Alfonso Basterra's lawyer argued in her closing argument that it was not coherent to let the girl out alone at five in the afternoon if after ingesting lorazepam at lunch she should be in a semi-comatose state and anyone could see her or stop her in the street.

[88][85] This would imply a temporal inconsistency with the camera from the Galuresa petrol station, in whose images Rosario and Asunta are in their car on their way to Teo at 6:21:24 pm.

[89] The cash register of the shop was not examined because two months had passed, but the testimony of the witness that she recognised Asunta and her father on the day of her death was believed by the Jury, although the time was not known with total certainty.

For two months, before the contribution of the testimony of the classmate, the agents of the investigation and the examining judge assumed that Rosario had stopped in double line to pick up the girl.

In the conversations recorded during their detention in the prison cells, the mother asks Alfonso twice if he left the house the afternoon of Asunta's disappearance, which indicates that they did not meet in the street because the question would not make sense if she had seen him.

[81] The verdict did not discuss the possible motive for the murder, which the investigation also failed to clarify satisfactorily,[107] giving rise to numerous hypotheses and conjectures with little real basis in the press and social networks.

On 16 March 2016, the High Court of Justice of Galicia dismissed the appeals of the lawyers of both parents and confirmed the 18-year sentence, although it acknowledged that it was Rosario who suffocated her daughter.

[103] On 22 November, the Supreme Court also dismissed the appeals of the defence, acknowledging that there was no evidence of Alfonso Basterra's presence in the house where the murder allegedly took place, but condemning him all the same "as he participated on an equal footing with Rosario Porto and intervened in essential acts that led to the execution of the criminal act", "without the intervention of the appellant [Alfonso Basterra] the macabre outcome could not have been carried out".

On 24 February 2017, after it was announced that she was going to be transferred to the prison of A Lama, in Pontevedra, she was found unconscious due to an intake of sleeping pills that she had been accumulating and had to be admitted to a hospital.

[113] She was subsequently transferred, and on 12 November 2018, in her new prison, she tried to take her own life by hanging herself in the showers with the cord of a sweatshirt around her neck, but the sudden appearance of another inmate saved her.

The Professional Association of Journalists of Galicia and the Faculty of Journalism of the University of Santiago de Compostela criticised in a statement the news treatment given to the Asunta case.

[118][119] The BNG, Galician Nationalist Bloc, took this criticism to parliament and asked the Xunta, Government of Galicia, to promote compliance by the public and private media with codes of ethics in cases of violence involving minors.

[129] The series features several high-profile Spanish actors such as Candela Peña, Tristán Ulloa, Javier Gutiérrez, María León and Alicia Borrachero.

Civil Guard Ríos states that Rosario Porto acted alone and then Alfonso Basterra decided to support her and pretend with her that someone had kidnapped her daughter; on the other hand, the version given by judge Malvar is that they both did it because the girl knew a secret that could destroy them.

When in chapter six, minute 6', the civil guard investigators reveal photographic evidence which strongly suggests that the witness who saw Alfonso with Asunta in the street could not really have seen them, the examining magistrate dismisses their research, stating that the recordings merely show a time difference which may be interpreted in a variety of ways.