Let's take the case of Jason Young. He claimed that he was hundreds of miles away at the time of the murder. Should the prosecutor ask what he was doing when he was hundreds of miles away, or should the prosecutor ask him why he switched shoes during the murder? The answer is obvious, and that is how it works when a prosecutor cross examines a murder suspect like Knox.
Exactly. There were a gazillion examples in the Arias trial. One I remember off the top of my head, Juan Martinez was questioning about Jodi talking to a psychiatrist (who we later found out was Dr. Samuels). She said she "realized" what had
really happened after she talked to him, or something along those lines. No one had heard of him up to that point, except for counsels and Jod, the jury didn't know who he was.
Juan asked her, when did you first talk to him?
She said oh, I don't remember when it was.
So he veered off the subject momentarily. Then came back to it. Then he said, something like, "so in June 2010 you talked with Dr. Samuels......," and then Jodi said, "no actually it was February 2010." (I don't know what exact months were said, but the point is she apparently took offense to Juan saying that it was later than it really was, because it looked bad for her the later she told the "real truth." Her meeting with him was actually earlier than what he said, is what I remember).
Then Juan goes, "oh what was that?" And Jodi goes, "yeah, you said June 2010 but it was actually February 2010, not June." hahahahahaahahhaha.
Then Juan goes, "oh so you
do remember that, oh I see. Okay, so in February 2010....."
Then in later testimony when Dr. Samuels actually came on the stand, come to find out that Jodi was right and it actually
was whenever she said it was.
So now does anyone believe Juan, who knew everything about the case, would get the date wrong, and wrong by months?
No, he did it to trip her up. To show that she was lying. That she actually remembered extremely well when it was she talked to him. That her memory was actually very good.
And the most important............that she had lied to him originally when she said "I don't remember." Because it was very, very clear, that she had lied.
It is very very normal and routine for prosecutors to try to trip up suspects on the stand during cross-examination in order to catch them in lies in front of the jury. Because if the jury sees first-hand that they're lying, obviously that is going to make an impact.