Hundreds of suspected telephone and internet scammers were repatriated to stand trial China on Monday following a sweeping arrests in Indonesia and Cambodia.

A total of 254 mainland suspects were escorted by 286 Chinese police officers on four chartered flights from Jakarta and Phnom Penh to airports in Shanghai, Hangzhou, Guangzhou and Beijing.

The suspects, which also included Taiwanese citizens, are believed to be responsible for 3,000 fraud schemes in Hong Kong and 20 mainland provinces.

Their cases will mainly be handled by authorities in Shanghai and Guangdong province, home to most of their victims.

The arrests were possibly due to cooperation between authorities in Hong Kong, mainland China, Taiwan and Indonesia, and represent an historic haul of suspected scammers.

In August, the central government’s liaison office in Hong Kong blamed a spate of phone scammers posing as liaison office officials on mainland Chinese abducted and coerced by Taiwanese criminals in Southeast Asia to conduct the scam calls.

Ryan Ho Kilpatrick

Ryan Ho Kilpatrick is an award-winning journalist and scholar from Hong Kong who has reported on the city’s politics, protests, and policing for The Washington Post, Los Angeles Times, TIME, The Guardian, The Independent, and others