Police are hunting for a British boy feared to have been abducted in Spain and flown to eastern Europe.
The six-year-old, who lives in the coastal resort of La Antilla on the Costa de la Luz close to the country's southern border with Portugal, has not been seen since last Friday.
Davy Thompson, father of schoolboy David, reported him missing on Monday.
He has pointed the finger at the youngster's mum, his 48-year-old Polish ex-partner who has been named locally only as Mirka.
A court in the Spanish border town of Ayamonte is said to have asked Interpol to help track down the pair over fears David's mother could have headed back to Poland or flown to London where they holidayed last year and Mirka is understood to have friends.
Local reports said Mr Thompson had recently been awarded full custody of the youngster following a series of court cases after a number of years of joint custody.
Police chief Ezequiel Romero confirmed: 'The boy's father has reported him missing.
'We're talking about a British man who says the boy's mum should have returned him and hasn't.
'The mum is Polish and she appears to have had her phone switched off now for more than 24 hours.
'Given the possibility she could have taken the child, we are investigating and are trying to establish hers and the child's whereabouts.'
He added: 'We never rule out any possibilities. In principle it appears to be a family problem between the mum and dad but obviously we can never rule out anything.'
Mr Thompson said: 'I'm very worried. His mum had visiting rights from Friday to Sunday but on Sunday she didn't return my son and I reported him missing to the police.
'His mum is not at home, her car's not there, she's not answering her phone and he's not going to school.
'I've no idea where he is.'
Speaking outside a local court on Tuesday, he added: 'It's possible she could have taken him to Poland.'
His expat dad's lawyer Juan Carlos Gomez said he had been acting for Mr Thompson over a number of years in civil and criminal complaints which began when she 'falsely accused' her ex-partner of domestic violence in a case which led to his acquittal.
Claiming she took their son to Poland last August without Mr Thompson's knowledge or permission, he added: 'Her phone is constantly switched off. We suspect she has taken the child.
'We hope the work being done by the police and the courts to find them is accelerated because time is of the essence.'
The court in Ayamonte investigating the youngster's disappearance in conjunction with the Civil Guard is expected to issue an international arrest warrant for the British boy's mum if the missing pair are not located in the next few hours.
The youngster's grandmother told local press her son had won six court cases against David's mum and their main concern after her recent custody defeat was she could decide that if 'I can't have him, no-one can.'
Rosario Sanchez added: 'The most important thing for us is that we get him back safe and well. I haven't eaten or slept for two days.'
Mr Thompson's lawyer Juan Carlos Gomez confirmed his client had been born in the UK to a Spanish mum and British dad and still lived in Britain.
He said his client had lived in Spain for a number of years.
Speaking on Wednesday he added: 'David and the mum are still missing.
'She's a seasonal worker who works on farms. She was supposed to return the youngster on Sunday but didn't.
'There's a possibility she could have taken him to Poland or London where she has a friend and there's another possibility that she could have left the area with a new partner but it's all speculation and not really something I can comment on at the moment.
'Davy's son was born in Spain and as far as I know he doesn't have a passport.
'We understand his mum took him to Poland last year without the dad's consent which could mean she could have obtained a passport for the boy without his knowledge.
'I'm not aware at this stage that an international arrest warrant has been issued for her but the police are obviously looking for her and the youngster as a matter of urgency.'
Although David's mum is known to friends as Mirka her full name is believed to be Miroslawa Duk.
She has lived in Lepe near to La Antilla for a number of years.
This article has been adapted from its original source.
© Associated Newspapers Ltd.