It seems like just yesterday that Jodi Arias was on the stand for 19 days, testifying in her own defense in an attempt to escape a murder conviction for the death of Travis Alexander. She failed on that count, and was convicted of first degree murder in May of 2013. The next step is the penalty phase, where jurors decide whether or not she will get the death penalty. Prior to August of 2002, a Judge was responsible for such a decision but with the enactment of Arizona's new death penalty statute, the decision is now a jury's responsibility. 

The first step in the penalty phase is the presentation of "aggravating factors." Under Arizona law (Title 13 Chapter 751), the prosecutor has to prove at least one aggravating factor beyond a reasonable doubt in order for the death penalty to become a sentencing option. Aggravating factors are circumstances which increase the outrageousness of a given crime, and in Arizona they are defined by the statute. There are 14 aggravating factors enumerated in the statute, and here Martinez alleged that Arias committed the offense in an especially heinous, cruel or depraved manner. (See Title 13 Chapter 752 Section F7 of the Arizona statute.)

In 2013, prosecutor Juan Martinez presented evidence of the "especially cruel nature of Arias' crime," calling to the witness stand the medical examiner Kevin Horn to speak to the pain and suffering Travis Alexander experienced at her hands. Horn was extremely effective: he showed autopsy pictures of Alexander's 30 stab wounds and ultimately convinced a jury of Arias' guilt and cruelty. But when it came to the mitigating phase, the jury hung. So what now?

Under Arizona law, Martinez has one more opportunity to convince a jury that the death penalty is appropriate. If he fails, Arias gets to live and the judge will determine her penalty: a life sentence or life with the possibility of parole in 25 years. Jury selection in this critical second penalty phase of the trial starts today and is expected to last at least a week. Jurors will be vetted to ensure that they can be impartial, whether or not they know about the case. 

Once a jury is impaneled, Martinez will again present evidence of Arias' cruelty as an aggravating factor. If he fails to be convincing, the death penalty is off the table. But if he is able to prove it beyond a reasonable doubt (as he did in 2013), the jury will hear from the defense who will state applicable "mitigating factors." Under the Arizona statute, mitigating factors are "any factors proffered by the defense...that are relevant in determining whether to impose a sentence of death, including any aspect of the defendant's character" (AZ Title 13 Chapter 13 Section 751G). These factors do not have to be proven beyond a reasonable doubt but by the lesser preponderance of the evidence standard. And jurors don't have to agree with each mitigator unanimously. 

In Arias' first trial, foreman William Zervakos stated he voted against the death penalty in part because Arias did not have a history of violence. This is something the defense is likely to stress here too. The defense will also have to decide whether to call Arias to the stand in her own defense, which ended disastrously for her during the trial. If just one juror finds that the death penalty in not appropriate here, Arias' life will be spared.  

No matter what happens, the case will be automatically appealed to the Arizona Supreme Court, which reviews the conviction and sentencing for any kind of error. Arias can also apply for post-conviction relief for reasons such as ineffective assistance of counsel (which she has already alleged on numerous occasions) and discovery of new evidence. She can also file a Writ of Habeas Corpus (Under 28 USC Section 2254) and allege that her constitutional rights have been violated. Finally, given that Arizona Attorney General Tom Horne has indicated he won't issue any warrants of execution until a review of the recent execution of Joseph R Wood III is complete, Arias will not see a lethal injection needle for some time - if ever.

For Travis Alexander's family, however, this penalty phase has been a long time coming - but with jury selection beginning this week, they are at least a step closer to a resolution.   

Heather Hansen is a partner in the O'Brien and Ryan law firm who has been named one of the 50 top female lawyers in the state by Pennsylvania Super Lawyers. Heather is also a national television and radio legal analyst and journalist who has appeared extensively on CBS News, Fox News, Fox Business Channel, Fox.com, CNN, HLN and Sirius XM radio. Her writing has appeared in Law360 and she has co-authored two chapters in medical texts regarding medical malpractice litigation. Follow her on Twitter at @imheatherhansen.