JACKSONVILLE, Fla. -

Despite a series of rallies and calls for her release, Marissa Alexander was sentenced Friday morning to 20 years for firing one shot into a wall during an argument with her estranged husband.

Alexander, 31, claims she fired a shot from a handgun into the wall to protect herself during a confrontation with her husband, who she said had abused her. Because his two children were with them when she fired a shot in his direction, she was charged with three counts of aggravated assault.

Alexander's attorneys used the "stand your ground" law as part of their claim of self-defense during the trial, but prosecutors said it didn't apply because she left the room, got a gun and returned to confront him.

"She got two shots at her self-defense theory," State Attorney Angela Corey said. "Neither a judge nor a jury bought it."

After emotional testimony from Alexander's parents, sister, brother and 11-year-old daughter at Friday's sentencing hearing, Judge James Daniel sentenced Alexander to 20 years without parole. Daniel said he had no leniency under Florida's "10-20-life" law that requires someone convicted of firing a handgun during the commission of a felony to serve 20 years.

"The legislature has not given me the discretion to do what the family and many others are asking me to do," Daniel said.

Alexander was credited for 458 days she has already been in custody.

"Where is the compassion? Where is the justice?" U.S. Rep. Corrine Brown said after the sentencing. "It does not stand today in Jacksonville and is unacceptable."

Corey said she personally met with Alexander and reviewed the evidence in the case. She said Alexander was offered a three-year sentence before the case went to the trial despite her case qualifying for a 20 year minimum mandatory sentence.

After the hearing, an outraged Brown confronted Corey over the sentence.

"We explained to her that when she discharges a firearm in the direction of human beings, that the legislature says it’s dangerous and one of the reasons is because the bullet went through the wall where the children were standing," Corey said.

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Corrine Brown vs Angela Corey (smaller) "Three years is not mercy and 20 years is not justice," Brown told Corey. "If there ever was a stand-your-ground case, it was this one. But my feeling is that your office initially overcharged her in this case."

UNCUT:  Corrine Brown's outrage |
Exchange of Angela Corey, Rep. Brown

Brown said a white man was convicted of murder in Jacksonville on Friday and sentenced to 15 years. She said she has been in contact with some of the best domestic violence attorneys in the country and will be involved in the appeals process.

"This is the beginning, not the end," Brown said of Alexander case. "Clearly there is institutional racism."

Alexander's attorney, Kevin Cobbin, said she continues to believe she fired that shot in self-defense.

"Ten-20-life is not meant for people like Marissa Alexander," Cobbin said. "She's never been in trouble, has a Ph.D. The lady is a great mother to her own kids and her step-children. And the law is not made for her. The legislature did not think about people like her when they made the law."

Alexander's case has attracted support of several community organizations and national media attention as she was portrayed as a victim of domestic violence.