Tongdaeng, Thai monarch Bhumibol Adulyadej's favorite dog and the subject of a biographical book by the ailing king, died just days after a man was arrested under the country’s defamation laws for making a “sarcastic” remark about it. According to a statement released by the veterinary faculty of Kasetsart University late Monday, the dog died while “sleeping and relaxing” on Dec. 26.

The statement, which affixed the Thai honorific “Khun” — a title that roughly translates to "ma'am" — ahead of the dog’s name, reportedly added that it had been ill for the last few years and was just over 17 years old when it died.

The dog, which was rescued by the Thai king from an alley in 2002, regularly featured in palace photographs and was also the subject of a privately-funded animated film released earlier this year. However, outside the country, the royal dog grabbed headlines earlier this month when a military court charged a Thai factory worker, Thanakorn Siripaiboon, for allegedly insulting the monarchy through a disparaging remark about the canine on Facebook.

Thailand’s strict lese majeste laws make it a crime to insult the monarchy. If convicted, Thanakorn faces nearly 40 years in prison, even though the details of what the alleged Facebook post said have not been revealed.

Arrests and convictions under the sedition laws have surged since the military grabbed power in a coup last year. The army has also relentlessly cracked down on journalists, academics, politicians and students, detaining them for “attitude adjustment” sessions at military camps, leading to accusations that it is exploiting the lese majeste laws to stifle criticism and dissent.

King Bhumibol, 88, is the world's longest-serving monarch and is widely revered in Thailand, where his economic and social teachings are extensively read and promoted. Over the past two years, he has spent much of his time in hospital and has rarely been seen in public. His last public appearance was two weeks ago, when he swore in dozens of judges at a reception room in a Bangkok hospital.