MARIETTA, GA -- A potential juror told a court she is convinced of Ross Harris's guilt, and that the only remaining question was whether he would be executed.

Harris is accused of murdering his 22 month old son Cooper. He contends he accidentally left the child in his car seat on a sweltering June day in 2014. The heat killed the toddler.

The case isn't a death penalty case, but the unidentified juror was apparently unaware of that when she filled out a questionnaire, stating that in her mind, the only outstanding question was one of sentencing.

The court is trying to pick a jury in the Harris case, a trial which is expected to go on for weeks. Twenty-one potential jurors had been qualified by Wednesday. As many as 50 may be needed.

Every juror has indicated they've heard of this high profile case, so the challenge is finding jurors who know about it but haven't formed an opinion. Sometimes the jurors themselves can't even decide.

Juror 31 was female, previously employed as a restaurant server, now working as a paralegal. And her opinions about the case had changed markedly between the time she filled out her jury questionnaire and the time she appeared in court for questioning.

"What she said on the questionnaire and what she said in court were diametrically opposed," said Judge Mary Staley.

For example the jury questionnaire asked if Juror 31 was interested in serving on this case

"She wrote no because I know he is guilty. K-N-O-W -- I know he is guilty," said Maddox Kilgore, a defense attorney reading from her questionnaire. The juror was questioned Tuesday.

Prosecutors liked juror number 31. Harris's attorney wanted to dismiss the juror – even though the juror said emphatically in court under questioning that she could hear the evidence objectively.

"It certainly is more than just a little bit curious how we go from absolute knowledge of guilt to no opinion whatsoever," Kilgore said.

"It's illogical," said Judge Staley.

Meantime, a former pro football player was among the potential jurors questioned in the case. The player – whose anonymity is protected by the court – said he had heard of the case and could try the case objectively.

Juror 38 says his cousin was a murder victim in Mississippi a decade ago, and he said he was satisfied with the justice system's treatment of that case. Juror 38 told the court he was impartial to Ross Harris – whose attorneys are expected to challenge police testimony about his son's death.

"Are you going to believe a police officer's testimony just because they're a police officer?" asked Kilgore.

"No sir," answered the juror.

"You're going to give basically the same -- weigh it the same as you would any other witness?" Kilgore asked.

"I would say so. I'm kind of driven off information. So if the information is credible, it makes sense, that kind of thing I'll follow it. If not, discredit it."