Brenda Cecilia Agüero was born on 2 June 1995 in Buenos Aires, Argentina. She grew up in a family with her mother and two sisters, later moving to Río Ceballos, a town in Córdoba Province. At the time of her arrest, she lived with her mother and sisters in the outskirts of Río Ceballos. Agüero trained as a nurse and graduated with excellent academic results in 2018. She initially worked at a private hospital in Córdoba from 2019 until December 2020, when she resigned to focus on her position at the Ramón Castillo Neonatal Hospital.

During her early career, there were no public reports linking her to misconduct. She worked in the neonatal unit, caring for newborns in critical and routine medical situations. Those who knew her professionally described her as competent and attentive, although later testimony from colleagues during the investigation revealed suspicions about her behavior, such as volunteering for tasks outside her normal duties and wearing long-sleeved shirts even in hot weather.

Agüero maintained that she loved her job and denied any wrongdoing. After her arrest in August 2022, she abstained from testifying in early proceedings and later accused a male nurse of being responsible for the deaths, claiming he was present at the incidents “all the time.”

Between March and June 2022, an unusual spike in infant deaths occurred in the neonatal unit of the Ramón Castillo Neonatal Hospital in Córdoba, Argentina. All the affected babies were previously healthy. Initial theories from health officials suggested possible hospital-acquired infections or malpractice. However, suspicions of foul play grew when no new deaths occurred after twenty hospital employees were suspended.

Investigators ordered exhumations of the deceased infants, revealing abnormal potassium levels in their bodies, levels that could not have occurred naturally. Medical examiners determined the potassium and insulin had been injected, often while the babies were clothed, in the resuscitation room. The injections were delivered into their backs, bypassing standard intravenous methods.

Prosecutor Raúl Garzón led the case, and on 20 August 2022, Brenda Cecilia Agüero, a nurse at the hospital, was arrested. She was charged with five counts of aggravated murder and eight counts of attempted murder. She was placed in pre-trial detention at Bouwer prison, kept isolated from other inmates for her safety.

A psychological assessment concluded that Agüero was mentally competent, showed narcissistic and psychopathic traits, and lacked empathy for the victims’ families. The prosecution presented evidence that she had searched online for potassium and insulin dosage in newborns and that she had PDFs on neonatal drugs and CPR in her phone. Witnesses, including the mother of a surviving baby, testified that they saw Agüero handling the infants shortly before they decompensated.

The trial began on 6 January 2025, with Agüero maintaining her innocence throughout. Testimony from doctors and medical professionals confirmed that the babies died from deliberate injections of potassium or insulin. Police reports indicated that Agüero was present and actively involved in each incident. The prosecution argued that she caused the crises to gain attention when she attempted to resuscitate the babies.

On 18 June 2025, after months of testimony, a jury found Agüero guilty on all counts of murder and attempted murder. She was sentenced to life imprisonment. Ten other officials, including former provincial health authorities and hospital administrators, were also tried for their alleged role in concealing the deaths.