XI'AN, China -- In the heart of one of China's famed dynastic capitals, now a modern metropolis of eight million, Li Jianli lay partially paralyzed on a hospital bed with his skull smashed in and his speaking ability reduced to a few simple phrases -- "yes," "thank you" and so on. Only recently has Mr. Li begun to regain his ability to move and talk. The recovery has been slow and painful and tenuous, his relatives said.
Then there is the emotional trauma. When Mr. Li was asked on a recent afternoon to talk about the events that led to his hospitalization, his wife quickly stepped in to change the topic. "Even now, when he talks at length about the events of that day, he gets upset and begins to cry," she said later in the hallway. She asked to be identified only as Ms. Wang.
What happened to Mr. Li, 51, was the ugliest known episode among anti-Japanese protests that convulsed cities in China last month after a longstanding dispute over an island chain erupted into fury. Mr. Li's only offense, apparently, was driving a Japanese car. He ended up the victim of a mob that stopped the car on a wide boulevard in the middle of Xi'an.
Now, even as anti-Japanese sentiment remains strong, Mr. Li has become a symbol for many Chinese of what can go wrong when latent nationalism spins out of control.
"These protests could be a very important turning point in China's democratic politics," Bai Yansong, a prominent commentator on state television, said on his program, "1+1." "Just because you have a just cause doesn't mean that the process can be illegal."
He added, "They're using the outer clothing of patriotism, but in fact they're committing a crime."
The violence done to Mr. Li by one protester who beat his head was vividly captured by a bystander in a video that has become an Internet phenomenon. The police in Xi'an, the capital of Shaanxi Province, began a manhunt for the attacker and asked people around the country for help. Last week, the police announced that a man had been arrested. Xinhua, the state news agency, said the suspect could face the death penalty if convicted.
With the territorial conflict between Japan and China over the Diaoyu Islands -- called the Senkaku by Japan -- still simmering, another diplomatic flare-up could prompt more protests and riots. During the rallies last month, Ai Weiwei, the dissident artist, shot a video of protesters outside the American Embassy in Beijing attacking a sedan carrying Ambassador Gary Locke. Many Chinese have attributed the Japanese government's recent purchase of the islands to an American conspiracy.
In a sign of continuing hostility, Japanese automakers announced Tuesday that sales of Japanese-brand vehicles in China had plummeted in the last month.
In Xi'an, a slogan on a billboard by the airport expressway says, "The Diaoyu Islands belong to China."
Today, there are barely any signs of the protests in central Xi'an. Witnesses said it took a few days for city workers to clean up a pool of Mr. Li's blood, but the street is back to normal. People looking closely at cars, though, can see that there are now small Chinese flags affixed to many of them, in particular those of Japanese make.
Many liberal Chinese and foreigners have been asking whether the central government stoked the protests, or at least allowed them to go on unabated for too long. At the protests in Xi'an, which were among the most violent, the police were out in force, but some officers did not try to stop rioters from overturning police cars of Japanese make, several witnesses said. The attack on Mr. Li took place within 500 feet of a police station.
Mr. Li was driving home with his wife on Sept. 15 in a white Toyota Corolla after they had spent the morning looking at construction materials for their son's new apartment, Ms. Wang said. Not far from the western gate of the ancient city wall, they encountered a crowd of protesters waving Chinese flags, chanting slogans and smashing cars.
Protesters quickly encircled the Corolla and used batons, bricks and bicycle locks to smash the car with the couple inside.
The two stepped out of the car to plead with the protesters to stop. Details of what happened next are murky, but the Internet video shows a heavyset man leaping at Mr. Li and delivering four blows to the back of his head with a bicycle lock. In the video, the sharp sound of metal whacking against skull can be heard above the din of the crowd. Ms. Wang screamed for help as she sat on the ground trying to stop the blood flowing out of her husband's wound.
As protesters continued to smash the car, one bystander yelled: "Can we first save this guy? We are all Chinese. Have you started to take him for a Japanese?"
With the help of a few bystanders, Ms. Wang dragged her husband across the street and flagged down a taxi. At a hospital, Mr. Li underwent brain surgery.
"It was complete chaos; my heart was thumping," Ms. Wang said. "How could they be so heartless?"
She added: "We heard that at the time the police did not dare to intervene. If they intervened, the situation would have become even more chaotic."
Last week, Mr. Li was able to walk a few steps for the first time since he was hospitalized. He is scheduled to have another surgery in six months. Doctors say he may never fully recover. Ms. Wang said Mr. Li had been the main provider for the family.
"This is the kind of thing we see on television," she said. "We never thought it could happen to us."
Amy Qin reported from Xi'an, and Edward Wong from Beijing.
This article originally appeared in The New York Times.