The woman held by officers has been identified locally as a 61-year-old named only by her first name and the initial of her surname as Carmen M. Police are still trying to identify who the head belongs to but local media are reporting Carmen’s 67-year-old partner vanished in February. The woman who made the gruesome discovery after opening up the box because of the awful smell coming from it, had to be treated for a panic attack.
She lives in the same town as the woman being questioned by police, the seaside resort of Castro Urdiales near Santander in northern Spain.
A court in Castro Urdiales is investigating the macabre discovery.
A spokesman for the Civil Guard at its HQ in Santander confirmed: “A woman has been arrested following the discovery of a human head in a box at a property in Castro Urdiales.
“Another woman raised the alarm after opening the box and discovering what it contained inside.”
Civil Guard are understood to have raced to the flat near the town bullring where the box had been left on Saturday.
It was not immediately clear how long it had been in the property.
The man who disappeared in February is believed to be Spanish. He has not been named.
Tests are now taking place to confirm whether he is the person the head belongs to.
In the 1995 crime thriller film Seven, Brad Pitt and Morgan Freeman star as detectives pursing John Doe played by serial killer Kevin Spacey.
The film ends with a horrific twist when the head of Brad Pitt’s character’s wife Tracy, played by Gwyneth Paltrow, is delivered by courier in a box and dropped off in the desert.