Eleven suspects from the Chinese mainland who were part of Shanghai's largest telecom-fraud case were escorted to Shanghai by police on Thursday, xinmin.cn reported.

A resident of the municipality's Pudong New Area, surnamed Lu, reported to police on Oct 28 that he was cheated out of 20 million yuan ($3.3 million) in the telecom fraud. Police later discovered that the suspects' calls to Lu originated in Cambodia.

After a monthlong investigation with Cambodian police, Shanghai police arrested 21 suspects in Phnom Penh on Dec 9. The 10 who are from Taiwan were handed over to Taiwan police.

The suspects had engaged in telecom fraud for years by pretending to be police officers and prosecuting attorneys, police said.

The alleged mastermind, who the other suspects say is in Taiwan, has not been captured.