A Minnesota teenager sent to prison for life after being convicted of killing her newborn baby rejected a plea offer Friday that could have freed her within seven years.

Nicole Marie Bee­croft, then a 17-year-old high school senior in Oakdale, was sentenced in 2008 to mandatory life in prison without parole for stabbing the infant girl as many as 135 times before tossing her body into a trash can. She goes to trial Monday on the original first-degree murder indictment, but with hope of a different outcome.

Had Beecroft and her attorneys taken the offer from the Washington County attorney’s office, she would have pleaded guilty to a lesser charge of second-degree intentional homicide. The rejection left prosecutors shaking their heads, but defense attorney Luke Stellpflug said after the ­pretrial hearing that additional expert witnesses who hadn’t testified in the first trial would prove that the baby was born dead and Beecroft will be acquitted.

What happens in the Washington County courtroom this coming week will be watched closely in ­Minnesota because the Beecroft case is considered a textbook ­example of the type of case affected by a recent U.S. Supreme Court opinion that cast doubt on mandatory sentences for teenagers who commit murder. While not excluding mandatory sentences, the ruling said courts must weigh mitigating factors of youth before imposing sentences.

“It has ripples in the criminal justice system throughout the country,” Fred Fink, chief of the criminal division in the Washington County attorney’s office, said of the high court’s Miller vs. Alabama ruling.

Last year, a divided Minnesota Supreme Court ordered a new trial for Beecroft in Washington County on grounds that interference from the Dakota County attorney and a medical examiner not connected with the case undermined her defense. At issue was whether other medical examiners they discouraged from testifying in her first trial could have shown that the baby was born dead, thereby negating the murder indictment.

“The state can’t prove live birth without reasonable doubt,” Stellpflug said after Friday’s hearing. “This time justice will prevail.”

Beecroft opted for a bench trial before Chief District Judge John Hoffman, which gives her another chance at avoiding a conviction. If she’s again found guilty, Hoffman then would explore a sentence through the prism of the U.S. Supreme Court ruling. He said in a hearing in January that the court could impanel a sentencing hearing as “a necessary remedy” to explore constitutional questions raised in Miller vs. Alabama about how children are different from adults when they ­commit crimes.

Now 24, Beecroft has been imprisoned for the past five years and is being held at the Washington County jail until her trial concludes. At the hearing, Hoffman expressed his condolences to Beecroft for the recent death of her mother while she wept.

She was a senior at Tartan High School when her baby was found dead; Beecroft had disguised her pregnancy from others, even her mother, according to court documents.

Beecroft’s attorneys, in a motion hearing in January, attempted to persuade Hoffman that he should dismiss the first-degree murder indictment altogether because the U.S. Supreme Court ruling in effect negated the charge against Beecroft. The ruling determined that mandatory life sentences without parole for defendants younger than 18 violates the Eighth ­Amendment’s prohibition on “cruel and unusual punishments,” said defense attorney Christine Funk.

Prosecutor Karin McCarthy objected, saying an indictment doesn’t constitute a punishment and because ­Bee­croft hadn’t been convicted or acquitted in her new trial, it was premature for the court to consider the sentencing ramifications of Miller vs. Alabama.

“It’s clearly an issue that has complications. I agree with all of you about that,” Hoffman said in January before denying Funk’s motion.

Barry Feld, a University of Minnesota law professor specializing in juvenile justice, has described the Bee­croft case as “particularly a textbook example of what is wrong with mandatory sentences that don’t allow any consideration of individual circumstance or culpability.” The U.S. Supreme Court made clear that “children are different,” he said, and judges now have discretion in sentencing.

Much of Friday’s hearing dealt with disagreements between Funk and prosecutor Siv Yurichuk over which autopsy photographs would be admitted as evidence in the trial and when they were made available.