The detained Chinese head of Interpol, Meng Hongwei, is being investigated for alleged bribe-taking, Chinese authorities have announced.
Mr Meng was first reported missing in late September after travelling from Interpol HQ in France to China.
His wife has revealed that he sent her a text message with a knife emoji on the day he went missing.
Mr Meng is the latest high-profile target to be ensnared in a sweeping anti-corruption campaign.
He is also a vice-minister for public security in China.
In its announcement of the investigation, China’s Public Security Ministry said the probe was “correct, wise and shows the determination of [President Xi]’s administration to continue its anti-corruption drive”.
Interpol is the global policing agency that coordinates between police forces around the world, including searches for missing and wanted persons.
Interpol’s general secretariat oversees the day-to-day work of the 192-member organisation, with the role of the president largely ceremonial.
After Mr Meng’s disappearance was made public on Friday, speculation had mounted that he had been taken into custody. A number of top Chinese government officials, billionaires and even an A-list celebrity have vanished in recent months.
Last week, actress Fan Bingbing, who disappeared in July, emerged with a public apology and a fine of 883 million yuan ($129m; £98.9m) 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’s anti-corruption blitz.
What has Interpol said about the matter?
In a statement on Twitter on Sunday, it 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.
On Saturday, the international police agency had urged China to clarify Mr Meng’s status, saying it was concerned about the well-being of its president.
What did his wife say?
French authorities have opened an investigation and have placed Mr Meng’s wife under police protection after she received threats.
Grace Meng, speaking shortly before China’s confirmation of the detention, had 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 emoji, 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.”