China has got its hands on 2500 dissidents who were living overseas.

In some cases this was done by kidnapping. In some cases, China used Interpol. Some returned "voluntarily" after China used their relatives as hostages.

Sometimes ordinary extradition sufficed, since China does not hesitate to fabricate accusations of nonpolitical "crimes".

The US has used relatives as hostages to try to make people spy for the US.