Twenty-two years on, Chinese authorities have removed from the capital former political and military officials with first-hand knowledge of the 1989 military crackdown on Tiananmen Square protests.
Calls to the Beijing home of Bao Tong, former top Communist Party aide to late ousted premier Zhao Ziyang, went unanswered on Thursday.
Bao, who has been under house arrest since his release from a seven-year jail term in the wake of Zhao's fall, typically writes political essays marking "sensitive" anniversaries in the ruling Party's history, arguing for democratic change.
"I think they probably left the day before yesterday," Bao's Hong Kong-based son, Bao Pu, said on Friday. "There have been arrangements made for them to visit some hot springs."
"My father has always refused this in the past, but this year there have been orders that he must not be allowed to give interviews, not even on the phone," Bao Pu said.
"They will probably be back on June 5 or 6."
A source close to People’s Liberation Army Lt. Gen. Xu Qinxian, who served a five-year jail term for refusing to lead his 38th army troops into Beijing on the eve of the crackdown, said Xu had been relocated to the northern city of Shijiazhuang in February.
Xu, 75, was told to leave following the publication of an interview with him in Hong Kong's Apple Daily newspaper in February.
"The next day he was sent to Shijiazhuang. They won't let him live in Beijing," the source said. "They're being very strict."
"He used to spend most of his time in Beijing, but they won't let him come back now."
A second source said they had recently discussed the crackdown with another veteran.
"I ran into one guy and we got talking," the second source said. "We started talking about Tiananmen Square, and then he told me a bit later that he was one of the troops that carried out the crackdown."
"He said it took days to wash the blood off Tiananmen Square ... and that they had kept photos to bear witness to history."
According to the diaries of Zhao's successor, the deeply unpopular hardliner Li Peng, no blood was shed during the move into the Square on the night of June 3.
"Who says no blood was spilled on Tiananmen Square?" the source quoted the retired soldier as saying.
No form of public memorial has ever been held for those who died when the People’s Liberation Army cleared thousands of protesters from the center of the city.
Instead, police regularly clamp down on any form of public protest or discontent at this time of year.
The Tiananmen Mothers, a group representing the victims of the crackdown, including those who died or were maimed, accused the government this week of making secret compensation deals with some victims.
Group member Zhang Xianling said she and a few other relatives of victims had bought flowers to take to a location near Tiananmen Square to make a memorial tribute to those who died.
But she said police had stepped in to warn them against the plan.
"They told us we weren't allowed out, that none of us was allowed to leave home, including Ding Zilin," Zhang said.
"I can go out, but wherever I go, there is someone following me, and they won't let us hold a memorial at a sensitive location."
Fellow group member Xu Yuzhi said the police guard outside her Beijing home had been stepped up in recent days, with three or four officers watching her movements day and night.
The Tiananmen Mothers, headed by retired Beijing University professor Ding Zilin, has tried to compile lists of victims and the places that they died, as well as calling annually for an official reappraisal of the protests and the crackdown which ended them.
Beijing residents say this year's clampdown is particularly harsh, coming hard on the heels of dozens of arrests of dissidents and lawyers amid fears of a "Jasmine" revolution inspired by recent uprisings in the Middle East.
This year also marks the 90th anniversary of the founding of the ruling Chinese Communist Party on July 1, with the authorities ordering a slew of patriotic TV programs and public celebrations.
Meanwhile, an activist in the eastern province of Jiangsu said police had swooped on a group of people wearing T-shirts with the slogan "Tiananmen, 8964" printed on them.
"As far as I know there were about four or five of us detained," said Yangzhou-based activist Gu Zhihua. "I don't know where the [leak] came from, but yesterday they knew that we were wearing the T-shirts."
"We were detained for about seven hours," Gu said.
Police had also detained a group of rights activists in the southwestern province of Guizhou, by taking them "on holiday."
"They told me I'd have to leave town [on Friday]," said Guizhou-based activist Quan Linzhi said. "The day after that is the June 4 [anniversary]."
"They are worried something will happen, so they are taking the whole group of us on a trip to keep an eye on us," he said. "Du Heping [and friends] have already left, and Chen Xi, too."
"I heard they were going to keep us in a hotel ... for five days."
Reported by Qiao Long for RFA's Mandarin service, and by Hai Nan for the Cantonese service. Translated and written in English by Luisetta Mudie.