Spanish police say they have arrested an American couple on suspicion of reckless homicide after the badly decomposed body of a child was found at their family home in the northeastern city of Girona.

A 39-year-old man and a 38-year-old woman with American citizenship are in detention prior to being questioned by an investigating magistrate, according to a police statement.

The arrest was made Tuesday at the couple's two-story apartment where they lived with their three children, police said. The father is an engineer, but it wasn't immediately known how long the family had been living in Spain, police said.

The child's body was found lying on a bed, under several blankets, police said.

Police said an autopsy had been ordered, but didn't say how old the child was.