A 22-year-old man from China named Liu Guosheng was charged on Monday with stabbing a 19-year-old student in Hong Kong after an argument about the protest movement.

Liu, who told the court he is employed as a chef, reportedly confronted a group of people in a pedestrian tunnel that has become known as the “Lennon Tunnel” because pro-democracy activists love to cover its walls with Post-It notes. Walls covered with Post-Its conveying messages of support for the protest movement are known as “Lennon Walls” and are a popular means of activist expression.

After arguing with the people in the tunnel for a while, Liu departed and returned with a fruit knife, which he used to stab a student named Hung in the neck and abdomen. Hung was dressed in black, as protesters are inclined to do, and was handing out leaflets at the time of the attack.

“The man suddenly rushed to my friend and slashed (him) in the neck. Then my friend ran away towards this direction. After that he fell down and was stabbed in the abdomen with a knife,” a friend of Hung’s told reporters.

Hung was said to be in stable condition at Prince of Wales Hospital on Monday and has been transferred out of the intensive care unit. His injuries were so severe that images posted on social media showed his internal organs visible through the wounds in his abdomen.

According to the South China Morning Post, Liu is a native of Guangxi, China, who arrived in Hong Kong on October 18 and had a permit allowing him to remain for a week. Hung is a student at a Christian secondary school called Kau Yan College.

Liu has been charged with one count of “wounding with intent,” an offense that can carry a punishment of life in prison.