The wife of Meng Hongwei, incumbent president of Interpol who has been detained in secret by China, says she is not sure her husband is alive after he disappeared mysteriously last month, to turn up under investigation in China.

In an emotional interview with the BBC, Grace Meng said she and her children have been waiting for news of Meng Hongwei, who has not been seen or heard from since 25 September when he flew from France to China. “I tell them Daddy is on a long business trip … We want to hear his voice,” she said in an interview published on Friday.

In September she reported her husband missing after he sent her a cryptic message on WhatsApp saying: “Wait for my call,” followed by an emoji of a knife. After French police opened an investigation and Interpol appealed to Beijing for answers, Interpol received his resignation and Chinese authorities announced on 7 October that he was in their custody and under investigation for bribery.

Meng Hongwei was the first Chinese national to become president of the international law enforcement agency, and had been living in France with his wife and two children. He appears to be the latest victim of a years-long anti-corruption crackdown that most observers say is a thinly veiled political purge to root out rivals and officials disloyal to President Xi Jinping.

On 8 October China’s ministry of public security released a lengthy statement accusing Meng Hongwei of bribery, while hailing Xi and the need for “absolute loyal political character”.

Former Interpol chief 'held in China under new form of custody' Read more

“I think it is political persecution. I’m not sure he is alive,” Grace told the BBC. “They are cruel. They are dirty,” she said, referring to the ruling Chinese Communist party.

Meng Hongwei is likely in a new form of custody called “liuzhi”, overseen by the National Supervisory Commission (NSC), a super-agency created in March to investigate corruption throughout the government.

Liuzhi, or “retention in custody”, is meant to be an improvement on the system it replaced, “shuanggui,” a disciplinary process run by the party that was known for its use of torture.

Under liuzhi detainees can still be denied access to legal counsel or families for as long as six months, and human rights advocates do not believe it will be much better. In May the driver of a low-ranking official in Fujian province died after almost a month under liuzhi. When relatives saw his body it was covered in bruises and his face was disfigured.

Grace Meng has previously said she received a threatening phone call from someone claiming to know where she and her children live. The family is now under French protection.

Her speaking out is unusual for family members of fallen Chinese officials who normally remain silent and out of public view. “This thing shows … it means they can do anything. I can’t imagine. [There is] no limit. That is also for all of China now,” she said. “That’s why I must stand up and I don’t want any other wives and children like me.”