May 24, 2013 -- The man in charge of the jury that convicted Jodi Arias of murder but could not reach agreement on whether her life should be spared described the process as "gut-wrenching" and said he and his fellow jurors struggled to contain their emotions.
"We couldn't allow ourselves to be emotional on the stand," jury foreman William Zervakos said today on "Good Morning America." "We couldn't allow ourselves to show emotion [but] it was a different story when we got back into the jury room."
Some of the most emotional moments during the five-month trial came over the 18 days when Arias, 32, took the stand and described her relationship with Travis Alexander, the ex-boyfriend whom she was convicted last week of stabbing and shooting to death in 2008.
Arias pled for her life also during the sentencing phase of the trial, but Zervakos says her long stint on the stand didn't help her case, especially when she was cross-examined by the prosecutor.
"I think 18 days hurt her. I think she was not a good witness...I think the way the prosecutor was with her, he's known for an aggressive style. I think it'd be difficult for anybody," Zervakos said. "I don't think I want to sit on the stand for 18 days.
"We're charged with going in presuming innocence, right, but she was on the stand for so long. I don't think it did her any good," Zervakos added. "There were so many contradicting stories."
Arias had been branded a liar by the prosecution because she initially denied killing Alexander, then claimed two years later that she killed him in self-defense, citing Alexander's physical and emotional abuse.
Zervakos, for one, believed Arias' story that she was abused in the relationship, but not that she killed Alexander in self-defense.
"I'm very sure in my own mind that she was mentally and verbally abused," he said. "Now is that an excuse? Of course not. Does it factor into the decisions that we make? It has to."
Arias' appearance - from her blonde bombshell look while she was dating Alexander, to the more subdued look she presented in the courtroom with glasses, bangs and dark hair - that captivated the media and the public throughout the trial, seemed to captivate the jurors inside the courtroom as well.
"When I looked in the courtroom for the first time and looked who the defendant was, it's hard to put that in perspective when you look at a young woman and think of the crime and then think of the brutality of the crime," Zervakos said. "It just doesn't wash so it's very difficult to divest yourself from the personal, from the emotional part of it."
After the jury's hung verdict was read Thursday, leaving the case still open, one juror mouthed, "I'm so sorry," toward Alexander's family and prosecutors.
Zervakos says he and other jurors struggled greatly with seeing Alexander's family every day in the courtroom.
"Until you're face-to-face with people that have gone through something like that, it's something you really can't put into words," he said on "GMA." "I'm six feet away from somebody talking about a horrendous loss. If you can't feel that, then you have no emotion, no soul."
Arias' fate is now left up to the prosecutor, who will decide whether to retry the penalty phase. If he decides to try again for the death penalty, a new jury will be selected and both the prosecution and defense will present evidence and arguments over what sentence Arias should receive.
The retrial, in which Arias can either be sentenced to death or to life in prison, with or without the possibility of parole, would begin July 18.
The prosecutor's office has not yet decided what it plans to do.
ABC News' Colleen Curry contributed to this report.