Billionaire Thanathorn Juangroongruangkit heads the youth-oriented Future Forward Party which won more than six million votes in the March 24 poll, the first since a 2014 coup, with its message of ousting the military from politics.
It had joined an anti-junta coalition with six others claiming the right to form a government in the aftermath of the disputed vote whose full results are expected by May 9.
Earlier this week he posted on Facebook that police had summoned him to appear on Saturday to face a sedition charge relating to an anti-junta rally in 2015.
He said the charge was “politically motivated”.
Hundreds turned up on Saturday morning in front of Pathumwan police station in downtown Bangkok, wearing T-shirts bearing the tycoon’s face and shouting “Save Thanathorn!” while waving placards that said “Military, get out!”
While inside, he and his party members tweeted out photos of what was happening, showing Thanathorn affixing his fingerprints on the charges and representatives from foreign embassies and the UN observing the police procedure.
More than two hours later, he emerged from the station and told reporters he had been charged with “inciting unrest…. helping the suspect escape… and the illegal assembly of more than ten people” for his actions in 2015.
“We believe we are innocent. I did everything in good faith,” he said, denying the charges.
Before leaving the police compound, Thanathorn flashed a three-finger salute, a resistance symbol borrowed by Thailand’s anti-junta movement from the Hollywood movie “The Hunger Games”, as his supporters did the same while shouting “Thanathorn, fight, fight!”
The charismatic leader is already being investigated under Thailand’s Computer Crimes Act for allegedly spreading false information when he criticised the junta in a Facebook Live discussion last year.
Supporter Woranuch Sirithonchai, who travelled three hours from her coastal hometown of Rayong, said she supports Future Forward’s anti-junta policies and “progressive thinking”.
“This incident happened since 2015 so why do they just summon him now? It’s because he has gained popularity,” she said.