After a witness has been asked questions by the prosecutor, the defence lawyer then cross-examines the witness. The aim of the cross-examination is to test the accuracy of the witness’ evidence or to establish facts which support the defence case.
The defence lawyer can also test the credibility of the witness as to whether he or she should be believed. For example, the witness was really too far away to really see what happened.
A prosecutor can object to a questions asked by the defence lawyer such as a questions that is misleading, confusing, or harassing. The Judge will then make a decision about whether the question should be answered by the witness.
A witness may feel during the questioning that their evidence is under suspicion or that their honesty is doubted, but the process of cross-examination is not meant as a personal attack towards a person. It is to ensure that all sides of the case are told, and to establish the truth. The judge is there to assist the witness if they do not understand a question, and to see that they are treated respectfully.