Two boys have been held in northern Spain after their mother was found dead, “gagged with a bag over her head” in the back seat of her car.

Police are treating the death of the 48-year-old woman, named locally as Silvia Lopez Gayubas, as a murder. The two boys allegedly tried to disguise her death as an attempted kidnap.

A regional government spokesperson confirmed the victim’s older child, a 15-year-old boy, was arrested and is expected to appear at a youth court on Thursday.

The younger boy, a 13-year-old, cannot face prosecution because he is under the age of criminal responsibility in Spain. However, he has instead been identified and placed in a child protection centre.

The pair were held in a park in the town of Castro Urdiales, near the port city of Santander, at around 2.15am on Thursday morning.

Hours earlier, police had started hunting for them after finding their mother’s body in a car in a garage near the family home in the resort town.

Ms Lopez Gayubas is believed to have been killed in the vehicle and is said to have suffered a stab wound to the neck, as well as injuries caused by violent blows.

Initial reports said her body had been discovered in the boot of her car, but local media subsequently reported she was in the back seat, and had been gagged and had a rubbish bag placed over her head.

‘Kidnapped’

The local reports also said the boys’ grandmother had called 999 after the pair phoned her on Wednesday night to say they were being “kidnapped”.

Investigators are understood to be attempting to confirm their suspicions that the boys fabricated the abduction before disconnecting their mobiles.

Officials have described the boys as the victim’s children, with local reports claiming the pair were adopted by Ms Lopez Gayubas, and are originally from Eastern Europe.

Responding to news of Ms Lopez Gayubas’ death, the mayor of Castro Urdiales, Susana Herran, said: “Our feeling is one of absolute sadness. It is awful that things like this happen.”

She added that the boys’ father was working in the neighbouring Basque Country when the alleged incident occurred.

Speaking at a press conference, regional government spokesperson Maria Gomez Eugenia de Diego said: “We want to express our most sincere condolences to the victim’s family and friends at this terrible time for them.

“The loss of a person in these circumstances is a devastating blow for the community.

“Yesterday afternoon, around 8.45pm in Castro Urdiales, the Civil Guard confirmed a 48-year-old woman had died. She had signs of violence on her and was found inside a vehicle.”

She added: “The investigation carried out so far points to the apparent involvement of the children of the woman who has died.

“They were located around 2.15am this morning in the same town of Castro Urdiales.

“One, a youngster aged 15, was arrested on suspicion of involvement in the victim’s death, and the other, a youngster aged 13, was formally identified.

“This incident confronts us with the harsh reality of the implication of children in acts of extreme seriousness. The Civil Guard investigators are fully focused on establishing all the circumstances revolving around this case.”