China has confirmed it is holding the missing head of Interpol, Meng Hongwei.
Beijing said he was under investigation by the country's anti-corruption body for unspecified breaches of the law.
Mr Meng, also a vice-minister of public security in China, was reported missing after travelling from the city of Lyon in France, where Interpol is based, to China on 25 September.
Later, Interpol said it had received his resignation from the presidency with immediate effect.
Mr Meng's wife, Grace Meng, has told reporters that her husband sent her a knife emoji in a social media message on the day he went missing.
She said her husband's case would be under the scrutiny of "international law and international public opinion".
After days of speculation about Mr Meng's whereabouts, China's National Supervision Commission said in a statement that he was under investigation.
The commission handles corruption cases involving public servants.
Mr Meng is the latest high-profile disappearance in China, where a number of top government officials, billionaires and even an A-list celebrity have vanished in recent months.
Last week, actress Fan Bingbing, who disappeared in China in July, emerged with a public apology and a fine of 883 million yuan ($NZ2m) for tax evasion and other offences.
But correspondents say that Mr Meng's high-profile position at Interpol was once seen as a prize for Beijing, raising questions about whom he might have angered or what he might have done to be targeted as part of President Xi Jinping's sweeping anti-corruption campaign.
What has Interpol said?
In a statement on Twitter, Interpol said it had received Mr Meng's resignation with immediate effect. Under its terms it has appointed senior vice-president Kim Jong-yang of South Korea as acting president.
A new president will be elected for the remaining two years of Mr Meng's mandate at the general assembly in Dubai next month.
What did Mr Meng's wife say about his disappearance?
Grace Meng, speaking shortly before China's confirmation of the detention, told journalists she thought he was in danger.
She issued an emotional plea for international help to find her husband.
On the day he went missing, she said he had sent her a social media message telling her to "wait for my call", before sending a knife emoticon, signifying danger.
With her back to the cameras to avoid being identified out of fear for her safety, she held back sobs to read out a statement in Chinese and English.
"We are always connected by [our] hearts. He would support me in doing this. The matter belongs to fairness and justice. The matter belongs to the international community. The matter belongs to the people of my motherland."
When Mr Meng was appointed two years ago, one newspaper here wrote that it would "promote understanding abroad of China's justice system".
This is probably not what was envisaged back then. His "resignation" and apparent detention makes it clear that it's the laws of China - and the rules of it's governing Communist Party - that trump all else for any government official. Even if they're appointed to a job in France.
China's new National Supervision Commission said Mr Meng was being investigated for "violation of laws".
Importantly it didn't mention - as is often the case with high-profile detentions like this - the charge of "violating party rules". The anti-corruption body has targeted thousands of people in a relentless drive led by President Xi Jinping. There are also rumours that Mr Meng may have been purged because of his links to another senior party figure out of favour with the leadership.
Who is Meng Hongwei?
He was elected Interpol president in November 2016, the first Chinese to take up the post, and was scheduled to serve until 2020.
He headed the organisation's executive committee, which provides overall guidance and direction.
Mr Meng has 40 years of experience in criminal justice and policing in China, notably in the fields of drugs, counter-terrorism and border control.
After his election, human rights groups expressed concern that the move could help China pursue political dissidents who have fled the country.