The Bowie State University student charged with fatally slashing her randomly assigned roommate in their shared suite last year was acquitted Thursday of every charge against her, as jurors apparently believed she was acting to protect herself in a sprawling melee.

After about 21 / 2 hours of deliberation, jurors found Alexis Simpson, 20, not guilty of first-degree murder and a host of lesser charges in the September 2011 slaying of 18-year-old Dominique Frazier. They rejected even the idea that Simpson acted in a grossly negligent way in the death.

As jurors read each not-guilty verdict, Simpson licked her lips and shook her head. Acquitted of all the charges, she began to sob. Later, she declined to comment.

“Clearly, the jury felt she acted in self-defense,” said Christopher Griffiths, Simpson’s attorney.

Frazier’s family did not react audibly to the verdict and left the courthouse with sheriff’s deputies as escorts. One deputy turned reporters to another exit as the family left.

Prince George’s State’s Attorney Angela Alsobrooks said she was “absolutely stunned” by the verdict. She added that though she didn’t know what jurors were thinking, Simpson was a “sympathetic defendant.”

The verdict punctuated an emotional final day of Simpson’s trial — one in which the young woman delivered her first public account of the September 2011 incident that left her roommate fatally slashed.

By her telling, one of the three young women who had fought her earlier was trying to pull her into a room at Bowie State University’s Christa McAuliffe residence hall. Simpson testified Thursday that she swung a knife as she tried desperately to break away.

“I was just scared,” Simpson said. “I didn’t know what they were going to do.”

Jurors could have convicted Simpson of charges ranging from first-degree murder to involuntary manslaughter, depending on whether they felt her conduct was premeditated or intentional, and to what degree — if any — she acted in self-defense. Even if they concluded she acted in partial self-defense, they could have convicted Simpson of voluntary manslaughter. Defense attorneys had argued that she should be acquitted of all the charges because she acted only to protect herself.

Prosecutors had accused Simpson of instigating two fights with Frazier, the second of which led to the stabbing. In closing arguments, Assistant State’s Attorney Christine Murphy slowly traced Simpson’s steps as she retrieved a knife and went to her roommate’s room. “As she walked, she had time to think about what she was doing,” Murphy said.

Simpson acknowledged she hit Frazier first during the first brawl, but she claimed she was then attacked by Frazier and two others. She said that before the stabbing, one of those women tried to pull her into Frazier’s room.

“I thought that if I was to get the knife they would leave me alone,” Simpson testified.

Several other witnesses, including two who both sides agree were not involved in the brawl, contradicted pivotal portions of that account, testifying that Simpson claimed to have been “jumped” when she wasn’t.

Griffiths, the defense attorney, said those witnesses were “stretching the truth,” moved by the emotion of watching Frazier die and feeling guilty for not stopping the melee.

“She’s not the aggressor here,” Griffiths said of Simpson. “They are pushing her around. They are abusing her.”

Dressed in a gray pantsuit, Simpson, 20, sobbed loudly during portions of her testimony. She said the trouble with Frazier began almost immediately after Simpson moved into the shared suite at Bowie State, having just transferred from Clark Atlanta University.

Simpson testified that after she and her mother stocked the bathroom with supplies, Frazier “acted like she was kind of upset.”

Over the next few weeks, Simpson testified, tensions escalated. She said that after she relayed to Frazier that the shower drain was clogged with hair, Frazier “took offense.” Later, she said, Frazier sent her a profane text message, and the two argued. Simpson said that at one point, a friend of Frazier bumped her in the university’s cafeteria.

Simpson said she felt “intimidated” and asked to change rooms. She said a property manager said that no others were available and that, should she move out, she would be charged $600. The manager denied that in court.

“I felt uncomfortable, and I was just, like, I don’t want to live like that in my own home,” Simpson testified.

She said she began staying at her mom’s home in District Heights and at her boyfriend’s home in Mitchellville but returned to the suite before Bowie State’s homecoming.

She said she had just woken from a nap and received a phone call when the fracas began Sept. 15. Simpson testified that she turned off an iPod and went into the bathroom so she could hear her phone call. She said she then went back to her room briefly, and when she returned to the bathroom, Frazier barged in and hit her with the door.

Simpson testified that she and Frazier exchanged words, and she walked to Frazier’s doorway. She said Frazier told her, “Do you want to get choked again?” and slammed the door in her face.

Simpson testified that she returned to her room to take off her shoes, and when she came out, Frazier was again in the doorway. She said she and Frazier began to fight, and two of Frazier’s friends also hit her.

“I just wanted to get myself together to get out of the house,” Simpson said.

After the fighting ceased, Simpson went to her room and got a knife, she said. She said she knew Frazier owned a knife — which one of her friends said she had briefly picked up while inside her room during the dispute — although it is unclear if Simpson thought Frazier intended to use it. A friend testified she took Frazier’s knife and put it in a dresser.

Simpson testified that as she returned to the bathroom, Keaira Johnson, one of Frazier’s friends, tried to pull her into Frazier’s room — an allegation Johnson denied.

“I was scared,” Simpson testified. “I just wanted to cool down, splash some water on my face.”

Simpson testified that she swung the knife and apparently connected with Frazier, though she “never meant to stab her.” Frazier, she said, stumbled, clutching her neck.

“I started to panic,” Simpson said. “There was, like, foam coming out of her mouth. I didn’t know what to do.”

Simpson testified that she tried to call 911, and when that failed, she contacted her mother. She said the two met at her boyfriend’s home, and she changed clothes.

Simpson testified that she left her bag and pants with her mom. She said she did not remember what became of the knife.

“If I had it, it was in my purse, and I left all my stuff with my mother,” Simpson testified.

Simpson said she went to a police station after her mother tried to contact a lawyer. Police never found the knife.

Griffiths said Simpson now plans to “spend time with her family and readjust.”

“She’s been through a lot,” Griffiths said.