Ha Huy Hoang was sentenced to six years in prison for providing documents to the Chinese.
Analysts say varied coverage suggests a schism within the ruling Communist Party.
She and other protesters had asked Vietnam's National Assembly for help in disputes over confiscated land.
Police nab staff members of Conscience TV to deter them from airing video reports on social media.
His wife says the whereabouts of Tran Anh Kim are unknown.
Supporters welcome the release but call on Hanoi to free all political prisoners.
A group remembers their journey 40 years after the first refugees fled persecution.
Held for 12 hours, he is asked about his contacts with 'reactionary forces opposed to Vietnam.'