BANGKOK (Reuters) - Thai police said on Monday they were investigating a complaint by a political activist who said he had been abducted by a group of unknown men and then questioned inside a van for 12 hours before being dumped on the street.
Mongkol Santimetakul, 25, a volunteer guard for the protest movement, said at around 11 p.m. on Saturday on a street near his home in a province south of Bangkok he was bundled into a van by the men who placed a hood over his head and confiscated his phone.
He said he was asked about an anti-monarchy sign that was erected by protesters in a nearby area.
"I was told to sign some document, which I refused and also told to cease all activism," Mongkol told Reuters.
Youth-led protests since last year have been demanding the resignation of the military-backed prime minister, who first came to power in a coup, and also reforms to Thailand's powerful monarchy.
Mongkol, who filed a police complaint after he said he was dumped on the street around noon the next day, pledged to continue his activism.
Deputy Police spokesman Kissana Phathanacharoen said the alleged abduction was not conducted by police and an investigation was ongoing.
The Internal Security Operations Command, a military-linked security agency, also released a statement denying involvement after accusations against the agency appeared on social media.
Protesters also accused authorities of intimidation tactics after alleging police detained at least two other volunteer guards at the weekend, initially denying them access to a lawyer, before both were freed.
"These tactics by the authorities will only generate more anger among the protesters," Piyarat Chongthep, a protest leader, told Reuters.
Yingcheep Atchanont of the legal monitoring group iLaw said anyone who was arrested should have the right to see their lawyer or a relative before being charged.
Police declined to comment when asked by Reuters about the alleged intimidation tactic.
(Reporting by Panu Wongcha-um and Panarat Thepgumpanat; Editing by Ed Davies)