This is J. Michael Flanagan, the defense attorney for Dr. Conrad Murray. Murray is on trial for involuntary manslaughter in the death of Michael Jackson. Flanagan is a skilled and experienced attorney, but in many cases, I would disagree with his decision of pointing at a witness (in this case Dr. Thao Nguyen, Cardiologist). In particular, I would steer him away from pointing with his index finger. While this body language may certainly make the witness squirm and feel uncomfortable - and this may work to his advantage, he should weigh this against how the jury may feel. Pointing is considered a significant insult in nearly every culture and country around the World. If any jury member has empathy for the witness being questioned, she/he will feel as if they are being pointed at, chastised, and thus falsely persecuted along with the witness. Got empathy? Your jury does.
A better way to point would be with the whole hand, palm up. The fingers and arm should both be extended but relaxed.