(CNN) The wife of former Interpol chief Meng Hongwei, who dramatically vanished into police custody after returning to China in September, told the BBC she isn't sure her husband is still alive.

In an interview with the British broadcaster, Grace Meng said she has received threatening phone calls since the Chinese government announced her husband was in custody in early October.

"I think it is political persecution. I'm not sure he's alive. They are cruel. They are dirty ... They can do anything," she told the interviewer.

Then-President of Interpol Meng Hongwei disappeared after he took a flight back to China in late September. His wife, Grace, said at the time that the last contact she received from him was a text message saying to wait for his call, followed minutes later by a knife emoji.

She reported him missing to French authorities, who opened an investigation. Interpol sent an official inquiry to the Chinese government asking for the whereabouts of their missing president.

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