Parents allegedly killed their three-year-old daughter by jabbing needles into her heart and lungs in a suspected satanic ritual.
Maia Vallejos was tragically pronounced dead in the northern Argentinian province of Chaco.
Her 20-year-old mum and 19-year-old stepdad were captured on the outskirts of the village Quitilipi.
During an autopsy, one of the needles was found to be touching her heart.
An older needle was affecting Maia’s lung and is thought to have caused an infection that affected her vital organs and triggered a cardiac arrest.
Speaking after the suspects’ arrest, prosecutor Cristian Arana said: “We don’t want to say where they’re being kept because people in Quitilipi are outraged and we want to safeguard their integrity.”
Authorities are now probing all possibilities, including that of a satanic ritual.
A source close to the investigation told local media: “The investigation is ongoing but the authorities are working on the theory that the little girl’s death could be related to some sort of ritual.”
Maia lived with her mum and stepdad in a rundown house on the site of a lumber sawmill.
The workers there have already been questioned as part of the ongoing criminal probe.
The unnamed couple being held over the death have been made official suspects in a murder investigation.
Mr Arana said: “We are very focused on this investigation and don’t rule out any theory. We hope to have more information shortly.”
The little girl’s mum, said to be four months pregnant with a new child, has made a request through a defence lawyer to be placed under house arrest after being beaten up following her remand in prison.
Earlier this month, a twisted dad allegedly hugged and kissed his son before strangling him, as the child told him “Daddy, I’m sorry”.
Ismail Kilincer, 32, carried out the attack on Huseyin, 10, in the district of Karatay in the Turkish province of Konya at around 7pm on March 8, police claim.
Beforehand, he sent his wife Rabia Kilincer, 31, to the shops.
Kilincer reportedly told police: “I told my son that I was going to kill him. I apologised to my son, and hugged and kissed him.”
At this point, the child looked at his alleged killer and said: “Daddy, I’m sorry too.”
Kilincer said he sat on Huseyin’s legs and strangled him with his bare hands, it is claimed.
He was later arrested and detained.