Story highlights Parents ordered to appear in Spanish court Monday

Parents took Ashya King, 5, from British hospital without authorization, police say

The father says there was a disagreement over his son's course of treatment

The boy was taken to a hospital in Spain, where he was found

The parents who pulled their cancer-stricken son from a British hospital and spurred an international search for the boy have been ordered to appear Monday in a court in Spain, where they were arrested, police said.

Brett and Naghmeh King took their 5-year-old son, Ashya, who has brain cancer, to France and then Spain late last week, authorities said. Hotel staff members in Malaga, Spain, recognized Ashya and his family from media coverage and contacted police.

Authorities did not confirm what charges the couple will face, but say that "cruelty" could be one of them as suggested by British law.

British police have arrived in Spain to question the parents, Malaga police told CNN. The British Crown Prosecution Service will be working on extradition efforts.

The court appearance is part of a European arrest order that was issued by Britain against the couple.

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Their arrests came hours after Brett King publicly asserted that he and his wife are not kidnappers and are not neglecting their son.

"We were most disturbed today to find that his face is all over the Internet and newspapers, and we've been labeled as kidnappers, putting his life at risk, neglect," King said in a YouTube video posted Saturday

"We're very happy with his progress," the father said in the video. "We're not neglecting him."

The father is seen sitting on a bed with his son leaning against him. He points to a machine on the nightstand next to him.

"We've got loads of these feeds here. We've got iron supplements and we've got Calpol ," an over-the-counter medication, King said. "As you can see, there's nothing wrong with him. He's very happy, actually. Since we took him out of hospital, he's been smiling a lot more. He's been very much interacting with us."

British police say the boy's parents, Naghmeh and Brett King, took him without authorization from a hospital on Thursday.

Brett King defended his actions in the video made shortly before his arrest. He accuses two doctors at the hospital for not allowing him to seek proton beam treatment outside of Britain, even though he said he was ready to pay for the treatment himself.

"We pleaded with them for proton beam treatment. They looked at me straight in the face and said with his cancer, which is called medulloblastoma, it would have no benefit whatsoever." King said he then looked on the Internet and found sites in the United States, France and Switzerland on proton beam treatment that "said the opposite that it would be beneficial for him."

The University Hospital in Southampton issued a statement saying they are working with doctors in Malaga to ensure Ashya's welfare and "are delighted that he has been found."

"We are aware of the comments made online by his father," the statement said. "Throughout Ashya's admission we have had conversations about the treatment options available to him and we had offered the family access to a second opinion, as well as assistance with organizing treatment abroad."

After Ashya was taken from the hospital without authorization Thursday, the family -- including Ashya's six siblings -- boarded a ferry and headed to Cherbourg, France, that night, police in Britain said.

Interpol issued an international missing person notice to the agency's 190 member countries to help find Ashya.

While authorities were searching for the boy, Detective Superintendent Dick Pearson said Ashya is not mobile on his own, cannot communicate verbally and is supposed to be receiving constant medical care because of recent surgery and "ongoing medical issues."

"Without this specialist 24-hour care, Ashya is at risk of additional health complications which place him at substantial risk," Pearson said Friday.

After the parents' arrest Saturday night, authorities acknowledged they could face criticism.

"All of our efforts resulted from explicit medical advice that Ashya's life was in danger," said Assistant Chief Constable Chris Shead of Britain's Hampshire Constabulary.

"I am very aware that there are comments about the rights and wrongs of our approach, but when we are told by experts that any child's life is at risk we will make no apologies for being as proactive as possible."

Hampshire police said Ashya was taken to Materno Infantile Hospital in Spain and that the facility was communicating with Southampton General Hospital, where the boy had been removed by his parents.

It was not immediately clear what happened to the Kings' other children.

In the United states only a handful of hospitals offer proton-beam therapy after surgery, including Massachusetts General Hospital, where the late U.S. Sen. Ted Kennedy was treated for brain cancer in 2008. He died just a year after his surgery for malignant glioma.

That surgery was followed by six weeks of radiation. Kennedy wrote in a Newsweek magazine article at the time that he underwent proton-beam therapy.

The theory behind proton therapy is that its high-energy particles zone in specifically on the tumor and so do not harm the surrounding healthy tissue as much as the X-ray photons in conventional therapy, said Dr. Donald O'Rourke, associate professor of neurosurgery at the University of Pennsylvania School of Medicine.