On Saturday, quoting a source, Hong Kong-based South China Morning Post had reported that Meng, the first Chinese head of the worldwide law enforcement agency headquartered in France, was "taken away" for questioning by discipline authorities "as soon as he landed in China" in the last week of September.
The agency issued a statement yesterday demanding "clarification" from China after Mr Meng's disappearance.
In the role Meng has been entrusted with a number of sensitive portfolios, including heading up the country's counter-terrorism division, which saw him in charge of the response to several major incidents in China's fractious western region of Xinjiang.
It was not until almost midnight on Sunday that China finally provided an explanation, releasing a one-sentence statement which said that Meng was under the "monitoring and investigation" of anti-corruption party investigators.
As well as leading the International Criminal Police Organization as president, Meng is also a Chinese politician and former official from the Communist Party of China.
Meng is a senior security official in China as well as the head of Interpol.
Meng's wife said he had returned to China, where they are both from, to work and called on the worldwide community to find her husband. She says he sent an image of knife that day, she thinks as a warning he was in danger.
On Saturday, Interpol formally requested China to notify the organisation of Meng's whereabouts.
China is now in the sixth year of a vast anti-corruption campaign launched by President Xi Jinping that has netted thousands of officials and business executives.
She said the knife was his way to tell her that he was in danger.
She said that four minutes before Meng shared the image, he had sent a message saying: "Wait for my call".
"I'm not sure what has happened to him", she said.
Meng's wife went to police in Lyon on Thursday to report his disappearance, according to the French Interior Ministry.
Xi, China's most powerful leader since Mao Zedong, has overseen a harsh crackdown on civil society that is aimed at squelching dissent and activism among lawyers and rights advocates.
Earlier Sunday, at an emotional press conference in Lyon, Grace Meng spoke for the first time about his disappearance.
The French authorities said his wife had been placed under police protection after receiving threats.
She said she was taking the unusual step of speaking out because she felt a greater responsibility.
But Interpol has, in the past, denied this, saying its head does not intervene in day-to-day operations, which are handled by secretary-general Juergen Stock who is German.
The 36-year-old took to China's Twitter-like Weibo to acknowledge her wrongs, beg for her supporters" forgiveness, and apologise to "society, the friends who care about me, the public and the national tax authorities'.