(CBS News) GREENSBORO, N.C. -- It's getting very hot in the courtroom at the trial of former senator and one-time presidential candidate John Edwards.
This week's main witness was to face another round of tough questions Wednesday from Edwards' lawyers.
Cheri Young, wife of former Edwards campaign aide Andrew Young, was grilled by them Tuesday. They suggested she and her husband were interested not just in helping Edwards hide his mistress, but in making money.
Attorney Alan Duncan asked her, "You're interested in getting Mr. Edwards, aren't you?"
"Sir, I'm here to tell the truth about my experiences, about my life," Young replied. "It was a lie when we accepted paternity for your client, and that is why we are here today."
Defense attorneys also grilled the former pediatric nurse about her husband's motives, along with his use of the sleeping aid Ambien, and his drinking habit -- and above all, whether he could be trusted.
"Have you ever told anyone that Andrew Young is such an accomplished liar that not even you as his wife, can tell when he's telling the truth?" Edwards' attorney asked.
Cheri said she couldn't recall, but she denied her husband hatched the paternity plot.
At the end of the day, Edwards' lawyers showed a home video that Cheri Young shot inside the hideout of Edwards' mistress, Rielle Hunter. The defense argued the tape was an attempt at extortion, but Cheri Young said she was trying to document what her family was going through.
"This was proof that there really was a Rielle Hunter," she said.
During the cross examination, Cheri Young acknowledged that she and her husband made money off the scandal, saying, "Income, yeah. I'll take income," she said. "That's reasonable."
Some legal experts say the testimony could hurt the prosecutors' case.
"It shows, basically, both Andrew Young and his wife were out for themselves," observes former federal prosecutor Kieran Shanahan. "They were conniving, and there was a scheme. ... I wouldn't be surprised if the jurors are asking themselves, 'Why aren't the Youngs on trial?"'
Jurors may be hard-pressed to overlook how much money the Youngs made while hiding Rielle Hunter.
To convince the jury, the prosecution is expected to call witnesses who can corroborate their stories.
To see Anna Warner's report, click on the video in the player above.