Police questioned the wife of a British journalist after he shared unflattering photos on social media alleged to be of Thailand's Crown Prince.

Noppawan "Ploy" Bunluesilp, 39, the Thai wife of former Bangkok-based correspondent and author Andrew MacGregor Marshall, was questioned for several hours after officers searched her family home in Bangkok on Friday morning. 

Marshall, who covered Thailand for many years and is author of "A Kingdom in Crisis," which is banned in the country, shared photos on Thursday from German newspaper Bild that claimed to show Crown Prince Maha Vajiralongkorn, 63, sporting tattoos and wearing tight jeans and a vest t-shirt at an airport in Germany.

Marshall, a staunch critic of Thailand's monarchy who has not lived in the country for several years, said in Hong Kong on Friday that his wife had nothing to do with his work.

"Ploy has never been involved in my journalism," Marshall said in a video posted on Facebook.

Following his wife's release, Marshall said he was "very concerned that she has faced this ordeal." 

"It is very important for the international reputation of the Thai Junta and the Thai authorities they do not persecute innocent people simply because they happen to be related to me."

Critics targeted

Thitirat Nongharnpitak, commander of the Central Investigation Bureau in Bangkok, said the photos of the Crown Prince were altered.

"The culprit is Andrew MacGregor Marshall, who has violated lese majeste laws for several years," he said, adding "he has acted from overseas to attack" the royal family.

Marshall said that he had only shared the photographs from the German newspaper on social media and had nothing else to do with them.

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Thai authorities regularly sentence people to lengthy prison terms under the country's draconian lese majeste law, which carries terms of up to 15 years for comments or actions deemed insulting to the country's royals.

Local and foreign media based in Thailand routinely self-censor to avoid falling foul of the law.

Marshall is a robust critic of the royal family and the Thai military, which seized power two years ago and has targeted critics and curbed free speech.

As the health of Thailand's revered King Bhumibol Adulyadej wanes, there is particularly sensitivity surrounding the Thai monarchy, particularly succession which directly involves the Crown Prince.

Source: Al Jazeera and agencies