Story highlights Marissa Alexander fired a gun in the air when her abusive husband threatened her

No one was hurt, but she faces 20 years in prison on various charges

Alexander: "Had I not discharged my weapon at that point, I would not be here"

She hopes the case will be dismissed under the 'stand your ground' law

Marissa Alexander, a 31-year-old mother of three, is facing a mandatory 20 years behind bars. She had pinned her hopes for freedom on a motion for a new trial; that motion was denied Thursday in a Florida courtroom.

In late April, Alexander spoke to CNN as an inmate in the Duval County Jail in Jacksonville, Florida. "This is my life I'm fighting for," she said while wiping away tears. "If you do everything to get on the right side of the law, and it is a law that does not apply to you, where do you go from there?"

Alexander is referring to Florida's "stand your ground" law, a law that has come under scrutiny since the killing of Trayvon Martin. Unlike the Martin case, which involved one stranger killing another, Alexander's case involved her gun and her abusive husband.

On August 1, 2010, she said her husband, Rico Gray, read text messages on her phone that she had written to her ex-husband. She said Gray became enraged and accused her of being unfaithful. "That's when he strangled me. He put his hands around my neck," Alexander said.

She managed to escape his grip but instead of running out the front door, she ran into the garage, she said, to get into her truck and drive away. Alexander said that in the confusion of the fight, she forgot to get her keys and the garage door wouldn't open, so she made a fateful decision. "I knew I had to protect myself," she said. "I could not fight him. He was 100 pounds more than me. I grabbed my weapon at that point."

She went back inside the house, and when Gray saw her pistol at her side, she said he threatened to kill her, so she raised the gun and fired one shot. "I believe when he threatened to kill me, that's what he was absolutely going to do. That's what he intended to do. Had I not discharged my weapon at that point, I would not be here."

Alexander, however, said she did not aim the gun at her husband. She said she fired into the air intending to scare him away, and Gray quickly left the house with his two children. No one was hurt in the incident, but Alexander sits in jail facing a 20-year sentence on three charges of aggravated assault with a deadly weapon.

Gray admitted to a history of physical abuse. In a previous incident, Alexander said he beat her so severely she ended up in the hospital and he ended up in jail. "He pushed me, choked me, pushed me so hard into the closet that I hit my head against the wall and passed out for a second," Alexander said.

In a deposition for the case against Alexander, Gray backed up much of his wife's story. "I told her if she ever cheated on me, I would kill her," he said during the proceeding led by a prosecutor for State Attorney Angela Corey's office and his wife's defense attorney.

"If my kids weren't there, I knew I probably would have tried to take the gun from her," Gray said. "If my kids wouldn't have been there, I probably would have put my hand on her." When Alexander's defense attorney asked him what he meant by "put my hand on her," Gray replied, "probably hit her. I got five baby mammas and I put my hands on every last one of them except for one."

Alexander's attorney filed a motion for dismissal under the stand your ground law, but at that proceeding her husband changed his story. Gray said he lied during his deposition after conspiring with his wife in an effort to protect her. At the hearing, he denied threatening to kill his wife, adding, "I begged and pleaded for my life when she had the gun." The motion was denied by the judge.

Alexander was offered a plea deal by Corey's office, but she opted to go to trial. A jury found Alexander guilty in 12 minutes. She is baffled why invoking the stand your ground law wasn't successful in her case.

"Other defendants have used it. What's so different about my situation that it doesn't apply to me," she asked.

The local NAACP believes race may have played a role.

"There's a double standard with stand your ground," said Isaiah Rumlin, president of the Jacksonville chapter of the NAACP. "The law is applied differently between African-Americans and whites who are involved in these types of cases," he said.

Rumlin cited two cases in Florida with white shooters: One had a successful stand your ground defense and the other has yet to be charged with a crime. Online blogs are also raising the question of race. Last week, a spokeswoman for the Rev. Al Sharpton confirmed he, too, was looking into Alexander's story. When asked about race as a factor in her case, Alexander declined to comment.

CNN requested an interview with Rico Gray for this story. He agreed but later declined through a family friend, saying he was concerned that speaking publicly would put his life in danger. On Sunday, he resumed contact with CNN, offering an interview to "anyone who would like to pay." Monetary compensation for an interview is against CNN policy.

Thursday, after the motion for a new trial was denied, State Attorney Angela Corey told CNN affiliate WJXT, "(We) offered to take 17 years off of the 20-year mandatory ... I exercised that discretion and as late as the Friday before trial, before we were picking a jury on the following Monday, my two prosecutors were willing to let her take the three-year minimum mandatory," she said. "The internet is filled with contentions that she fired a warning shot as she was being choked. Nothing could be further from the truth."

Alexander's sentencing hearing is scheduled for next Friday, but the proceeding is a formality -- the judge has no discretion because her 20-year sentence is mandatory. Her attorney, Kevin M. Cobbin, tells CNN he will continue his client's fight on appeal.