Authorities accused the college music teacher of posting "hostile thoughts" and "profound anti-government material" on social media
Vietnam sentenced a music teacher to 11 years in prison on Friday for Facebook posts that allegedly undermined the one-party state, which has been accused of tightening the noose on online dissent.
Communist Vietnam has long jailed its critics but has come under fire recently for targeting users on Facebook, a popular forum for activists in the country where all independent media is banned.
Nguyen Nang Tinh is the latest activist jailed for his Facebook comments, including posts about a Taiwanese steel firm that dumped toxic sludge into the ocean, killing masses of fish in central Vietnam.
He also wrote about police brutality and land rights, both flashpoint issues in Vietnam.
Authorities accused the college music teacher of posting "hostile thoughts" and "profound anti-government material" on social media.
The 42-year-old was sentenced to 11 years for "producing, disseminating or spreading information and documents aimed at undermining" Vietnam, his lawyer Nguyen Van Mieng told AFP from central Nghe An province.
He got another five years probation.
The jail term was "too harsh", Mieng told AFP, arguing that prosecutors did not have sufficient evidence to link the offending Facebook account to his client.
Tinh's father Nguyen Ngoc Dinh insisted his son was innocent, saying he "only raised his voice against injustice in society".
"My son was very strong in court. He didn't admit the charges," he added, calling the trial "ridiculous".
Tinh was bundled into a car by police in May after taking his two young sons for breakfast.
His conviction comes just days after a dissident with Australian citizenship was jailed for 12 years in Vietnam on terrorism charges, along with two other Vietnamese nationals who got 10 and 11 years.
Vietnam has come under fire for cracking down on activists since a conservative leadership came to power in 2016.
Last year, the government passed a controversial cybersecurity law that critics say is designed to scrub online dissent.
The bill -- which is not yet implemented -- requires sites like Facebook and YouTube to remove content if asked by the government to do so. The law would also require companies to hand over user data and host servers in the country.
Amnesty International says there are at least 128 political prisoners behind bars in Vietnam, 10 per cent it estimates were jailed for Facebook posts.
Other rights group put the number of jailed dissidents as far higher, but no official data is available.