Timeline of Peng Shuai's apparent disappearance

The mysterious public retreat of tennis star Peng Shuai has sparked a #MeToo reckoning that has escaped China's internet firewall and rocked the international sports community.

Peng, 35, gained international acclaim in the tennis world after winning major titles at Wimbledon in 2013 and the French Open in 2014. She was formerly ranked No. 1 globally in women's doubles.

Last month, she accused a retired top Chinese Communist Party official of sexual assault and then seemingly disappeared from social media. As international concern for her mounted, she reappeared via correspondence released by Chinese state-run news outlets that backtracked her sexual assault claims -- which only prompted further global skepticism about her safety and whereabouts.

Here is a timeline of the saga that has spurred global backlash against China's handling of high-profile sexual assault claims, and put the nation's internet and media censorship policies under renewed international criticism just weeks ahead of the Beijing 2022 Olympic Games.

Nov. 2: 'I will tell the truth about you'

In a lengthy post on her verified account on Weibo, a popular Chinese social media platform, Peng accused Zhang Gaoli, the former vice premier of the Chinese Communist Party, of sexual assault and said she had a yearslong affair with him.

The post swiftly disappeared after being shared on Nov. 2, but screenshots of it circulated online in the following weeks.

"I have no evidence, and it is impossible to leave evidence at all. ... You are always afraid of what recorder I bring, leaving evidence or something," Peng wrote. "But even if I become like an egg hitting against a rock and like moths extinguished in the flame, I will tell the truth about you."

Nov. 16: Naomi Osaka tweets about Peng Shuai

As Peng's disappearance from the public eye began to raise international concerns, Japanese professional tennis player Naomi Osaka lent her voice to the growing social media search for her Chinese colleague.

"Hey everyone, not sure if you've been following the news but I was recently informed of a fellow tennis player that has gone missing shortly after revealing that she has been sexually abused," Osaka wrote. "Censorship is never ok at any cost, I hope Peng Shuai and her family are safe and ok. I'm in shock of the current situation and sending love and light her way."

Osaka has over a million followers on Twitter, and her tweet garnered over 93,000 likes on the platform.

Nov. 17: Chinese state-run media releases email allegedly from Peng

As global concern and calls for proof-of-life mounted, Chinese state-run media released an email that was allegedly written by Peng to the global Women's Tennis Association that back-tracked her sexual assault allegations.

CGTN Europe, an English-language arm of the state-owned China Global Television Network, tweeted a screenshot of the email Peng allegedly sent to WTA Chairman and CEO Steve Simon on Nov. 17.

The screenshot of the purported email opens with, "Hello everyone this is Peng Shuai," and says that the allegation of sexual assault is not true. "I'm not missing, nor am I unsafe. I've just been resting at home and everything is fine," the text of the note, posted by CGTN Europe, states.

ABC News cannot independently confirm that Peng penned the email broadcast by the state-run news outlet, and the WTA's Simon said he has a "hard time believing that Peng Shuai actually wrote the email."

"The statement released today by Chinese state media concerning Peng Shuai only raises my concerns as to her safety and whereabouts," Simon said in a statement to ABC News in November. "I have a hard time believing that Peng Shuai actually wrote the email we received or believes what is being attributed to her."

"Peng Shuai displayed incredible courage in describing an allegation of sexual assault against a former top official in the Chinese government. The WTA and the rest of the world need independent and verifiable proof that she is safe," Simon added. "I have repeatedly tried to reach her via numerous forms of communication, to no avail."

Simon called for Peng to be allowed to speak freely and for her allegation of sexual assault to be investigated with "full transparency and without censorship."

Also on Nov. 17, American tennis superstar Serena Williams posted a tweet calling for an investigation into Peng's allegations.

"I am devastated and shocked to hear about the news of my peer, Peng Shuai. I hope she is safe and found as soon as possible. This must be investigated and we must not stay silent. Sending love to her and her family during this incredibly difficult time," Williams wrote, adding the hashtag #whereispengshuai.

Williams' tweet garnered over 134,000 likes.

Nov. 18: China says Peng's case is 'not a foreign affairs matter'

The following day, Chinese Foreign Ministry Spokesperson Zhao Lijian dismissed questions about Peng's whereabouts at a briefing, saying: "This is not a foreign affairs matter. And I am not aware of the relevant situation you mentioned."

Nov. 19: UN calls for investigation, WH calls for 'verifiable proof' of her whereabouts

The United Nations called for an investigation into Peng's allegations of sexual assault on Nov. 19.

"As you know, according to available information, Peng, the former world double No. 1, hasn't been heard from publicly since she alleged on social media that she had been sexually assaulted," Liz Throssell, the spokeswoman for the U.N. High Commissioner for Human Rights, told reporters. "We would stress that it is important to know where she is and you know, her state, know about her well-being."

"We are calling for an investigation with full transparency into her allegations of sexual assault," Throssell added. "And I think we would say that that should be the case into all allegations of sexual assault. It is really important to ensure accountability, to ensure justice for the victims."

On the same day, White House press secretary Jen Psaki called on China to provide "verifiable proof" of Peng's whereabouts.

Nov. 21: IOC president says he had a video call with Peng

International Olympic Committee President Thomas Bach said he held a video call with Peng on Nov. 21.

Video of the call was not released, but a still image was. The IOC said in a statement that Peng thanked the IOC for its concerns about her well-being.

"She explained that she is safe and well, living at her home in Beijing, but would like to have her privacy respected at this time," the statement said. "That is why she prefers to spend her time with friends and family right now. Nevertheless, she will continue to be involved in tennis, the sport she loves so much."

The IOC said the call lasted 30 minutes and was joined by Emma Terho, chair of the IOC Athletes' Commission, and IOC Member in China Li Lingwei.

"I was relieved to see that Peng Shuai was doing fine, which was our main concern. She appeared to be relaxed. I offered her our support and to stay in touch at any time of her convenience, which she obviously appreciated," Terho said in a statement released by the IOC.

The IOC said Bach invited Peng for a dinner once he arrives in Beijing next January for the Winter Olympics, which she accepted.

Dec. 1: WTA suspends all tournaments in China and Hong Kong

WTA Chairman and CEO Steve Simon announced in a lengthy statement that the international tennis body was immediately suspending all WTA tournaments in China, including in Hong Kong.

Simon lauded Peng's "strength and courage" for coming forward with her allegation of sexual assault on Nov. 2.

"Since then, Peng's message has been removed from the internet and discussion of this serious issue has been censored in China. Chinese officials have been provided the opportunity to cease this censorship, verifiably prove that Peng is free and able to speak without interference or intimidation, and investigate the allegation of sexual assault in a full, fair and transparent manner," Simon said. "Unfortunately, the leadership in China has not addressed this very serious issue in any credible way. While we now know where Peng is, I have serious doubts that she is free, safe and not subject to censorship, coercion and intimidation."

Simon said the WTA has repeated its calls for a full and transparent investigation, without censorship, into Peng's accusation.

"The WTA will do everything possible to protect its players," Simon added. "As we do so, I hope leaders around the world will continue to speak out so justice can be done for Peng, and all women, no matter the financial ramifications."

He continued: "I very much regret it has come to this point. The tennis communities in China and Hong Kong are full of great people with whom we have worked for many years. They should be proud of their achievements, hospitality and success. However, unless China takes the steps we have asked for, we cannot put our players and staff at risk by holding events in China. China's leaders have left the WTA with no choice. I remain hopeful that our pleas will be heard and the Chinese authorities will take steps to legitimately address this issue."

Chinese state-run news outlet CGTN released an English-language statement from the Chinese Tennis Association expressing "indignation and firm opposition" to the WTA's decision.

Dec. 2: IOC says it held a 2nd video call with Peng, defends 'quiet diplomacy'

After criticism from some that the first video call was a publicity stunt, the IOC said on Dec. 2 that it had a second video call with her on Dec. 1 and defended its use of "quiet diplomacy."

"There are different ways to achieve her well-being and safety. We have taken a very human and person-centred approach to her situation," the IOC said. "Since she is a three-time Olympian, the IOC is addressing these concerns directly with Chinese sports organisations. We are using 'quiet diplomacy' which, given the circumstances and based on the experience of governments and other organisations, is indicated to be the most promising way to proceed effectively in such humanitarian matters."

The organization said that it was "reconfirmed" in the second call that Peng "appeared to be safe and well."

Dec. 19: Peng denies sexual assault allegation in cryptic video appearance

In the first time the public has heard Peng speak since the Weibo post on Nov. 2, the tennis star appeared to briefly answer questions in a video clip shared by the Singaporean Chinese-language news outlet Lianhe Zaobao.

Peng attended a cross-country skiing exhibition in Shanghai over the weekend amid the run up to the Beijing 2022 Olympics, where she answered a few questions on video from a reporter with Lianhe Zaobao. The Singapore-based news outlet is known to be Beijing-friendly, despite claiming editorial independence. It is one of the few news outlets that can employ local Chinese reporters on the Chinese mainland -- an ability not every foreign press outlet has in China.

"I've always been free to come and go," Peng told the reporter, according to a translation of the clip.

"First of all, I want to emphasize that it is very important that I never said anything nor have I written anything about anybody sexually assaulting me," she added when asked if she penned the email to the WTA shared by CGTN in November that back-tracked her claims.

When asked about her Weibo post, she said "it's a question of my personal privacy" and "there are a lot of misunderstanding[s], so there's nothing to say ... about this interpretation and distortion."

Finally, she said she wrote the Chinese version of the email to the WTA shared by CGTN, but her English "level is not good enough to translate."

"It's a translation, but the meaning and the message in the email I replied to Mr. Simon had hardly any difference," Peng said.

The WTA said in a statement to ABC News in response to the video that these appearances do not alleviate their "significant concerns."

"It was again good to see Peng Shuai in a public setting and we certainly hope she is doing well. As we have consistently stated, these appearances do not alleviate or address the WTA's significant concerns about her well-being and ability to communicate without censorship or coercion," the WTA stated. "We remain steadfast in our call for a full, fair and transparent investigation, without censorship, into her allegation of sexual assault, which is the issue that gave rise to our initial concern."

Meanwhile, searches for Peng on the Chinese internet still yield no current results.

ABC News' Karson Yiu, Christine Theodorou and Kirit Radia contributed to this report.