He has been asked to appear as a witness for the defence.

他已被传唤出庭为被告作证。

《牛津词典》

Singer Michael Jackson was probably addicted to the painkiller Demerol, a witness for the defence in the trial of his doctor, Conrad Murray, has said.

BBC: Conrad Murray trial: Jackson 'addicted to Demerol'

Jeffs, who had stood expressionless and silent before the jury for nearly half hour during his closing arguments, called only one defence witness to the stand - a man who read from Mormon scripture.

BBC: Warren Jeffs, polygamist sect leader, gets life in jail