HONG KONG - A man who posted photos of a puppy seemingly drowning in a washing machine has fled Hong Kong, after police said they had launched an animal cruelty investigation.

The man, who goes by the name of Jacky Lo, posted a status update on his Facebook page on Sunday in which he bragged that he was leaving for China, as outrage over the photos spread, the South China Morning Post (SCMP) reported yesterday.

"Wanted?? This afternoon I'm going back to China. See ya later," he said in his post.

It included a link to an online petition urging the police to bring him to justice, which has drawn nearly 20,000 signatures, Agence France-Presse news agency reported.

Hong Kong police said on Sunday they were investigating the case as one of suspected cruelty.

The pictures, which Lo posted last month, showed a small dog submerged in water and being spun around helplessly in the machine.

Lo posted comments in Chinese: "A super quick way to wash a dog: Soak, clean and dry. All done. Clean and quick!" He added a smiley icon and the words "feeling content" in English.

The photos went viral in the past week. In reply to a user who asked if he had killed the dog, he replied: "Yes (it's dead). Do you wanna see?"

Some of the posts claimed Lo is from the mainland and drew attention to photographs on his Facebook page that show him partying at luxury hotels, gambling in Macau and with expensive cars.

The Hong Kong Society for the Prevention of Cruelty to Animals said what was done was "truly horrific", SCMP reported.

Under Hong Kong laws, animal cruelty offences carry a maximum sentence of three years in prison and a fine of HK$200,000 (S$32,360).