Spanish police investigating the death of a man whose head was found in a box last week are now looking for the “big, black and heavy” trash bags that his partner ordered their cleaning lady to dispose of earlier this year, a report says.

Police believe the trash bags contain his body.

Carmen Merino, 61, of Castro Urdiales, is currently being held on suspicion of murder following the disappearance of her 67-year-old partner, Jesús Mari Baranda, in February, according to El Pais. A month after he vanished, Merino gave a box to a neighbor and friend for safekeeping, telling her that she wanted to get rid of some sex toys ahead of a possible search by police in connection to Baranda's disappearance, the newspaper added.

The friend finally opened the box last week after the smell emanating from it became unbearable – only to find Baranda’s “possibly burned” head inside, El Pais reported, citing sources close to the investigation.

The home in Castro Urdiales where the trash bags are reported to have been left. (Google Maps)

BRITISH MAN, WIFE ABDUCTED IN PHILIPPINES HOME, POLICE SAY

Authorities are now scouring a local landfill for the rest of Baranda’s remains after speaking with a cleaning lady who reportedly visited Merino’s home in February. She told investigators that Merino asked her to get rid of several “big, black and heavy” trash bags that were left on her property, in any way possible, according to El Pais.

Baranda was reported missing by one of his cousins in March.

A relative that spoke to El Pais said Merino initially told his family that Baranda “had gone on a trip” and got a new cell phone and number, yet his family started getting suspicious after the text messages coming from it didn’t read like things their loved one would say.

When confronted about the discovery of his head last week, Merino told police that, “I found it stuck in a box on the mat outside the front door and I kept it because it was the only thing I had of his,” according to El Pais.

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The motive for Baranda’s death is unclear – but El Pais reported that it might have something to do with money, as Merino was unemployed and without an income – and she continued collecting Baranda’s pension payments following his disappearance.