Authorities in the eastern Chinese province of Zhejiang have handed a 12-year jail term to an engineer who hacked into a local cable TV network, posting an image of the 1989 "Tank Man" taken during the military crackdown on the Tiananmen Square democracy movement, official media reported.

Wang Yibo broadcast slogans denouncing the ruling Chinese Communist Party to 465,000 cable customers via their set-top boxes in Zhejiang's coastal city of Wenzhou in August 2014, China Central Television said.

One message addressed the ruling party as "bandit communists" who had carried out "too many evil deeds."

Another superimposed the image of a lone man facing down a column of tanks in Beijing, which became an iconic representation of the 1989 bloodshed, but which is blocked along with all keyword searches linked to the massacre on China's tightly censored Internet.

Another slogan called for the release of veteran 1989 dissident Wang Bingzhang, while another said: "Don't cooperate with the communist devils," and another said "Our natural rights and freedoms have been stripped away and our homes have been occupied by the enemy."

Photos of the images taken by subscribers to the cable TV service circulating online included jailed Nobel peace laureate Liu Xiaobo, rights lawyer Gao Zhisheng, and New Citizens Movement co-founder Xu Zhiyong.

The captions described Liu Xiaobo as a "prisoner of conscience doing time for the people."

Bid for lighter sentence

According to CCTV, Wang said that he did it out of anger at a lack of career progression in his job at a technology company that serviced the cable network.

"I have been working at the same company for so many years, and I had a lot of pent-up resentment," Wang was quoted as saying.

"I wanted to do something that would allow me to vent that anger."

U.S.-based China scholar and former online editor Li Hongkuan said Wang's actions were most likely an expression of political dissent, and that he had agreed to cite personal resentment as a way of getting a lighter sentence.

"He is painting himself as a little guy, so that it wouldn't make sense for them to sentence him for life," Li said, adding that the tone of the slogans posted by Wang recalled the anti-corruption cries of the heroes of the 16th century epic Chinese novel, The Water Margin.

"He is playing down his own importance, so as to achieve a reduction in sentence, that's the way I understand it," he said.

'Unthinkable' actions

Wang's heavy jail term is a reflection of how "unthinkable" his actions were in the minds of government officials, Guangzhou-based writer Ye Du told RFA.

"From the government's point of view, to use a cable network to broadcast images which they regard as subversive, including those linked to June 4, 1989 ... in favor of freedom and democracy, is totally unthinkable," Ye said.

"They had to hand down a heavy jail term to act as a deterrent to others."

A netizen surnamed Liu said he believed the authorities had cut a deal with Wang to prevent him from drawing too much attention to the political message behind the hack, however.

"The government needed him to say this too," Liu said. "They have to reduce any politically sensitive happening to a question of ... morality so as to dilute the political point."

He said capable and highly educated Internet engineers like Wang pose a big potential threat to government control over citizens.

"They have the technology to discover the truth, and to understand what really happened," Liu said. "From time to time, people like that will have a huge impact on Chinese society."

"The case of Wang Yibo is an example of this."

Reported by Hai Nan for RFA's Cantonese Service, and by Shi Shan for the Mandarin Service. Translated and written in English by Luisetta Mudie.