Dmytro Bulatov has flown to Latvia. It was reported earlier that his final destination was Lithuania.
He appeared on TV last week with a gash on his face and part of his ear cut off. He said he had been held and beaten for eight days.
His case became a new rallying point for protesters, who want President Viktor Yanukovych to resign.
Thousands are currently in Maidan square, a focal point for the protesters.
Mr Yanukovych has offered a number of concessions and his cabinet quit their jobs.
But the demonstrators, many of whom want to see closer ties with the EU rather than Russia, have not been placated.
Mr Bulatov was a leader of a group called Automaidan, made up mainly of drivers who would protect the protest camps and blockade streets.
He went missing on 22 January and re-emerged eight days later the outskirts of Kiev.
He told the media he had been “crucified” by his abductors, who he could not identify other than to say they had Russian accents.
Opposition politicians Western diplomats expressed outrage at the incident.