The balancing process jurors follow in deciding whether to sentence someone to death is set in state criminal laws, according to criminal defense attorney William Tobolsky.

It is triggered by a determination by a jury that the killing is either by a defendant's own conduct, by someone he hired or by a drug kingpin.

In New Jersey, aggravating factors are specified by statute, and notice of them is given to a defendant long before the trial begins. They include conviction of another murder, even though the murder may have occurred at a later date than the one being considered by thejury. Other factors considered are murder to silence a witness, murder during the course of another felony such as burglary, robbery, rape or kidnapping; the murder of a law enforcement officer; or the murder of a victim under 18.

One factor still in the statute but rarely used is that the murder was especially vile or heinous. Because that area has proven to be "fruitful for appeal," it is now rarely cited, Tobolsky said.

The defendant does not have to list mitigating factors he hopes to prove until a jury has ruled unanimously that execution could be an appropriate sentence, a finding made at the end of the guilt phase of the trial. The factors must be related to the circumstances of the offense or the record or character of the defendant.

The defendant cannot argue that he did not commit the murder. The most common factors used by defense attorneys are severe emotional distress of the killer, or positive factors like a life of prior good works and a clean criminal record.

If jurors do not agree unanimously that at least one aggravating factor is proven beyond a reasonable doubt, the sentence is life in prison.

If they do agree on an aggravating factor, they then consider mitigating factors. They do not have to agree unanimously on those, Tobolsky said.

The vote on each mitigating factor is recorded on the verdict sheet.

The final decision is whether the aggravating factor outweighs the mitigating circumstances.

If jurors are not unanimous in that final question, the sentence is life in prison.