SONORA — After a week of testimony with no surprises, the trial of a mother accused of killing her son's alleged molester in April basically comes down to this: When or, more precisely, how did Ellie Nesler get her gun?

For the jury, which began deliberations late Thursday, Nesler's state of mind the moment she picked up the gun is critical in deciding whether she formed the requisite malice or intent to kill. If the jury decides that a blinding rage impelled her to take up her weapon--that the act was not premeditated--then manslaughter is the most serious charge on which she can be convicted.

Prosecutors contend that Nesler, a 40-year-old single mother of two, left her trailer home the morning of April 2 with the palm-sized .22-caliber semiautomatic in her car. She was intent on killing Daniel Driver, 35, a convicted child molester who was appearing at a preliminary hearing in nearby Jamestown on charges that he had sodomized Nesler's son, then 6 years old, and three other boys at a Christian camp here in 1988.

As the boy and Nesler waited to testify against Driver, prosecutors argue, the divorced mother steeled herself to make good on a promise of vengeance she had uttered numerous times over three years.

During a break in Driver's hearing--her first opportunity--prosecutors said a "calm and focused" Nesler walked up to Driver, who sat shackled next to his attorney, and pumped five bullets into his head and neck.

"She meant to, expected to, intended to kill Daniel Driver," said prosecutor Jo Graves in an hourlong closing argument Thursday. "We're talking about the murder of a man in custody in handcuffs. Empathy should never, never encompass coldblooded murder."

Defense attorney J. Tony Serra, in an impassioned two-hour closing argument that moved between shouts and near-whispers, offered an intricate story of how the gun wound up in Nesler's hands.

Serra said Nesler--a victim of child molestation--was pushed over the edge by a series of fast-moving events that morning.

First her son could not stop vomiting in anticipation of testifying against Driver, who had once threatened to kill the boy and his mother if he told anyone about the molestation.

Then, as Driver walked into the courthouse, he flashed a smirk at Nesler and the boy.

Finally, another mother testifying against Driver told Nesler in the hall outside the courtroom that her testimony was weak and that Driver "was going to walk."