The 43-year-old suspect, Sergeant Major Jakkrit Khomsing, is said to have tricked his victims through fake online dating profiles and Facebook accounts.
When he was arrested at his home in the northeastern province of Khon Kaen police found HIV medicine and later confirmed he was HIV-positive through testing.
Sgt Maj Khomsing is accused of creating fake Facebook accounts and profiles on the gay dating app Blued, where he found young Thai teens and began conversations.
Thinking they were chatting with someone else, his alleged victims – more than 70, who are aged between 13 and 18 – were persuaded to send him naked photos of themselves.
But when they finally met in person the teens realised they had been tricked. If they refused to have sex with them, Sgt Maj Khomsing said he would release the pictures.
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“Even though the suspect is a soldier, this behaviour – and I’ve consulted with army commanders – is a personal issue, not an organisational one,” he said.
Detectives in Thailand are widening their investigation and want to contact other victims of Sgt Maj Khomsing who have yet to come forward.