Thai police have arrested a top anti-coup activist who taunted the military government with a Facebook message reading: "Catch me if you can."
The military said officers tracked down Sombat Boonngamanong through the internet. He is wanted for violating an order to report to the ruling junta.
Mr Sombat led an online campaign organising rallies against the army's coup, which took place in May.
The military seized power in Thailand after continuing political unrest.
The move followed six months of political deadlock as protesters tried to oust the government of Yingluck Shinawatra.
But the army's removal of her elected government has drawn widespread international criticism.
Mr Sombat was arrested late on Thursday in the eastern Chonburi province.
"We have a team who tracked him through the internet," army spokeswoman Sirichan Ngathong told the AFP news agency.
Officials said soldiers and police were able to locate the IP address used by Mr Sombat to post his comments.
His arrest has been denounced by Amnesty International who described it as part of "a systematic and widening crackdown on key human rights" by the military.
"Sombat Boonngamanong should be released immediately unless he is charged with a recognisable criminal offence and remanded by an independent, civilian court," said human rights group's Asia director, Richard Bennett.
"This is the latest in a disturbing wave of arrests of people purely voicing disquiet about the military regime. The army's course of action is looking increasingly like a purge."
Hundreds were detained after the coup, but most have since been freed, correspondents say.
Meanwhile, corruption investigators have widened their inquiry into former Prime Minister Yingluck Shinawatra, investigating her private assets.
The National Anti-Corruption Commission's investigation is connected to a rice-subsidy scheme, in which the government bought rice from farmers at above-market prices to boost rural incomes.
The commission had already indicted Ms Yingluck over charges of dereliction of duty, saying that she failed to heed advice that the scheme was potentially wasteful and prone to corruption.
Ms Yingluck was detained last month at an undisclosed location as leaders of Thursday's military coup tightened their grip on power.
Mr Sombat previously led a pro-democracy group called Red Sunday, reports the BBC's Jonathan Head in Bangkok.
He was also one of the only prominent red shirt activists to defy the Thai military by taunting them from his Facebook and Twitter accounts, our correspondent adds.
Mr Sombat has urged followers to stage peaceful public rallies, and has encouraged the flashing of the three-finger salute from The Hunger Games films that has become a symbol of defiance against the junta.