In an interview with the Associated Press, Zhang said he was about 20-years-old when his unit, the 162nd motorised infantry division of the elite 54th Group Army's based in the central city of Anyang, was sent to Beijing on 20 April 1989.
On 3 June, orders came: drive to the square and get it cleared. He was serving as a medic and was unarmed in the final assault.
Mr Zhang said he knew of no deaths of unarmed civilians by the troops of the 54th army whose function was to surround the square. Most reports, he said, blamed troops from the 27th and 38th group armies based outside Beijing.
“I saw some horrific scenes,” he said, but declined to say more, for fear of reprisals. Afterwards he resigned in earnest from the army.
Back in his hometown of Tengzhou, where he still lives, he got involved in politics. On 14 March 1992 he was arrested and sentenced to three years in a re-education-through-labour camp for political crimes.
After searching his home police seized all his written material, including his diaries of the massacre
Since then he has written ten letters in total to President Hu Jintao, calling on him to shed light on that night. in his view the “responsibility [for the massacre] can't just be laid on the military. [. . .] It's really the responsibility of all Chinese.”
In 1989 “security personnel illegally attacked and destroyed patriotic youth in the name of the country. [. . .] To this day, there isn't a single government department which has dared to face up to this, to take on the case, or to investigate it,” he wrote in an open letter to President Hu dated 6 March.
Even 20 years later the country dare not speak of that night. Some accounts suggest that soldiers disposed secretly of the dead, in some cases killing the wounded.
Jiang Yangyong did try to talk about it. As a medical doctor he was on duty that night when 89 people were brought to his hospital with gunshot wounds.
In two letters to the government in 2004 Jiang said that on the basis of the wounds he observed on the victims, soldiers must have used fragmentation bullets which are banned under international conventions.
He accused the government of deploying soldiers from faraway regions who did not know what was going in Beijing and were led to believe that they were putting down an uprising by dangerous “counterrevolutionaries.”
He said that the army fired indiscriminately on anyone in the square, even on uninformed youth or those simply curious.
Because he called for investigations into the deaths, he was taken into custody by police on 1 June 2004 and held in an army guesthouse, where he was subjected to months of interrogation and “study sessions” to make him understand his mistakes and correct them.
He was eventually investigated for spreading rumours that demonised party and state.