Stephanie Erends’ defense attorney told jurors the Roseville woman “just snapped” the night she killed her longtime friend.

“In the heat of the argument, she just starts swinging, slashing and hacking at Alicia Ernst,” said Jonathan Richter, public defender.

That characterization, presented as opening statements got underway Monday, is at odds with prosecutors’ claim that Erends, 26, planned the killing on March 8, 2008. And it’s why Richter said his client should be found guilty only of voluntary manslaughter, which carries a maximum 11-year prison sentence, and not first-degree murder, as she is charged.

“This was not a cold, calculated attack from behind,” Richter said.

Dressed in a blue blouse, Erends spent most of the morning resting her head in her hands, sometimes rubbing her eyes. When prosecutors displayed images of Ernst’s mutilated body, she sobbed audibly.

Prosecutors say the women spent the night – Erends’ birthday celebration – getting high on methamphetamine before Erends drove Ernst out to a secluded area off Baseline Road. That’s where Erends got into the back seat of her Geo Metro, grabbed a wallpaper scraper, then reached around and slashed the throat of Ernst, still strapped into the passenger seat, they contend. Ernst, 24, a nurse who worked at an Auburn care facility, died after an intense struggle.

In tape-recorded interviews that prosecutor Garen Horst played for jurors Monday, Erends admits to the murder as well as plotting it for months. In one excerpt, she tells investigators she had bought the murder weapon before the killing to use specifically against Ernst. She said she broke the handle off of it in advance to make it “easier to use.”

“I took her over there. I killed her. That’s it,” an emotionless Erends said in a portion of the tape.

In previewing his case, Horst laid out a long and troubled relationship between the two women, characterized by intense jealousy.

“Alicia loved to dress up, to look nice. She got the guys. She also knew how to push the defendant’s buttons,” Horst said.

In interviews, Erends told investigators she killed Ernst because Ernst allegedly poured acid down her throat when she was asleep several months earlier. Horst said Erends also believed Ernst had slept with her boyfriend and felt slighted that Ernst’s family considered her a bad influence.

But Richter said Erends’ behavior before and after the killing doesn’t suggest premeditation. The purported confessions, he said, were made to get police off her back. And the murder weapon was in her car because she had been asked at her job to remove stickers from a store window.

He said Erends – who has three children — was trying to get her life back on track after a long struggle with drugs. Recently, she had completed career training and hoped to work in the medical field. And he said she made only perfunctory efforts to hide her crime after the fact.

“These are not the actions of someone who was planning to commit a murder – especially a murder that she could not possibly have hoped to get away with,” Richter said.

Erends, who also faces special allegations of lying in wait, is expected to testify in the trial. She faces up to life in prison.