Police have raided the Bangkok home of a British journalist's wife and questioned her for several hours in connection with his social media posts containing photographs purported to be of Thailand's crown prince - the heir apparent to the throne - wearing a crop top and sporting a huge tattoo on his back.

The 'insulting' photos Andrew MacGregor Marshall posted on Facebook on Thursday were published in the German tabloid newspaper Bild and were purportedly of Crown Prince Maha Vajiralongkorn at an airport in Germany. The crown prince spends much of his time in Germany.

The images, which Thai police say were doctored, show a man in low-slung jeans and sandals, with a huge sleeve tattoo holding a white fluffy poodle.

The German Bild newspaper and British journalist Andrew MacGregor Marshall claim this photo shows Crown Prince Maha Vajiralongkorn at an airport in Germany wearing a white crop top and holding a poodle

Thai police say the photos, which claim to show a heavily tattooed crown prince and his 'new wife', are doctored and break Thailand's strict 'lese majeste' law

He is pictured with a woman who Marshall claimed is Suthida Vajiralongkorn aka Nui, a former Thai air pilot who now acts as the crown prince's guard.

Marshall said in his Facebook post that Vajiralongkorn is the crown prince's latest wife.

'There is at least one error in the [Bild] article - it names the poodle as Foo Foo, but in fact Foo Foo is dead, and the poodle in the photographs is actually called Fee Fee,' Marshall wrote on Facebook.

He said that despite Bild being a tabloid newspaper he is 'convinced that the pictures are genuine'

Marshall said in a statement that his wife, Noppawan 'Ploy' Bunluesilp, was visiting Bangkok with their 3-year-old son when both of them were taken by police Friday morning to a police station along with Noppawan's father.

Armed with a search warrant, police also took computers and several items from the house.

Noppawan, who is Thai, and her father were released about eight hours later.

Noppawan Bunluesilp, wife of British journalist Andrew MacGregor Marshall, holds her son as she leaves a Bangkok police station on Friday

British journalist Andrew MacGregor Marshall holds up a photo of his wife Noppawan Bunluesilp at a hotel room in Hong Kong

Marshall said in his Facebook post that he believes the pictures of the crown prince at the airport are 'genuine'

Her release 'is very encouraging news but I remain very concerned that she has faced this ordeal. She is innocent and plays no part in my journalism,' said Marshall in a statement issued from Hong Kong, where he currently is.

Police Lt. Gen. Thitiraj Nhongharnpitak told reporters that Noppawan had been detained in connection with photos that Marshall had posted on his social media, and which were 'deemed inappropriate.'

Under Thailand's strict 'lese majeste' law, criticism of the monarchy is punishable by up to 15 years in prison. Lese majeste prosecutions have soared under the arch-royalist junta that seized power two years ago and styles itself as a defender of the monarchy.

Local and foreign media based inside the country must routinely self-censor to avoid falling foul of the law.

The prince's father, King Bhumibol Adulyadej, 88, is ailing in a hospital, putting the monarchy under stress as the country considers the prospect of its first royal succession since 1946.

Police Lt. Gen. Thitiraj Nhongharnpitak stands with Noppawan 'Ploy' Bunluesilp (left), wife of British journalist Andrew MacGregor Marshall

Noppawan 'Ploy' Bunluesilp, wife of British journalist Andrew MacGregor Marshall, prepares to leave a Bangkok police station after police raided her home

Thitiraj initially said officers had determined that the photos published on Bild's website were doctored, and that Marshall and two Thais, whom he did not name, were responsible for creating and posting fake photos on social media.

However, when questioned further by a reporter, he hedged his assertion, saying that 'whether or not they were doctored is not important — he should not have posted them in the first place.'

Detectives said on Friday that the pictures were fake and violated the kingdom's royal defamation law.

On Friday morning the online article on Bild was blocked in Thailand for carrying 'inappropriate content'.

Marshall, who used to be based in Bangkok, is a frequent critic of the Thai monarchy and the military government that has ruled since a 2014 coup. Marshall and his wife have not lived in Thailand since 2011, but he continues to write about the country and is banned from entering it.

Speaking to reporters after it was decided to release Noppawan, Thitiraj said police had always believed her 'to be innocent of her husband's crimes, but as police, we must follow the evidence.' He said Friday's actions gave her the opportunity to prove her innocence.

'She still is Thai and she still respects the Royal institution and she has nothing to do with it,' he said.

Police Lt. Gen. Thitiraj Nhongharnpitak (second right) watches Noppawan 'Ploy' Bunluesilp (center) as she address the media while leaving a Bangkok police station

Noppawan 'Ploy' Bunluesilp, wife of British journalist Andrew MacGregor Marshall, carries her three-year-old son after being released from custody

Marshall said Noppawan, 39, who used to work for Reuters and NBC, was not involved in his journalism.

'If Thai police believe that I have broken Thai law they should seek my extradition to Thailand via legitimate international legal challenges. It is unacceptable to harass an innocent woman simply because she is married to me,' Marshall, who also used to work for Reuters, said in his statement.

Lt. Gen. Thitiraj said police won't issue an arrest warrant for Marshall because he is not in Thailand and the matter would have to be discussed with other nations. He said her hoped Marshall would stop his 'movement' to criticize the monarchy.

'Andrew is the only foreigner who has consistently criticized the institution for four to five years now, and he hasn't stopped. He is the only one who has consistently attacked the institution.'