Custody is defined by the supreme court as happening when: a person has been taken into "custody." a person has been formally arrested. a person has been deprived of his freedom of action in any significant way. all of the above

I believe the answer is: All of the above

A person is considered to be put under custody if he/she no longer has the freedom to go to anywhere they want and has to be detained in a certain place.

The purpose of this is to make sure they attend the trial/hearing that would be conducted soon after.