Amanda, 27, somberly received the news as she stood in Camden County Superior Court on Thursday, the Associated Press reported.
Both the prosecutor’s office and Amanda’s attorney Jordan Zeitz did not immediately respond to PEOPLE’s request for comment.
After the judge handed down her sentence, Amanda issued a tearful apology, captured in a clip obtained by NJ.com, saying she never wanted her sister to die.
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“I know there’s nothing I can say to justify what I did,” Amanda said before completely breaking down. “I just want to make it clear that I never had intentions of taking my twin sister’s life. If I could take back what I did, I would in a heartbeat.”
“Having to live with the fact that she’s no longer alive is devastating,” Amanda continued. “I just want to apologize to my family for putting them through this. I hope that they can all forgive me.”
Zeitz spoke out on behalf of Amanda prior to the sentencing, explaining to Judge Edward McBride that the killing was a result of Amanda suffering from “postpartum depression” and “emotional issues” from pregnancy.
“She now is going to remember this for the rest of her life,” Zeitz said in court, according to NJ.com. “The sentence you are going to impose is going to pale in comparison to the life sentence she’s already serving.”
“We would ask that you follow what the family wants — to get her back to them so they can heal quicker,” Zeitz said, NJ.com reported.
Amanda’s family had pleaded with the judge to give Amanda a more lenient sentence, according to the outlet.
In September, Amanda pleaded guilty to stabbing Anna to death during an alcohol-fueled fight in late June.
Amanda admitted her role in her sister Anna’s brutal killing, pleading guilty to a reduced charge of second-degree manslaughter as part of a deal orchestrated by the prosecution.
Amanda was charged with aggravated manslaughter following the fatal June 22 incident.
Police were summoned to an apartment in Camden shortly before 5:30 a.m., arriving to find Anna Ramirez on the ground with blood on the left side of her chest. She had been stabbed once, and was pronounced dead at the hospital an hour later.
According to the police report on the killing, previously obtained by PEOPLE, Anna “initiated a physical altercation with [Amanda] by striking her in the face.”
Amanda told police her sister went into the house, got a knife and approached her. “Amanda Ramirez stated she struggled with her sister for control of the knife, and she ultimately stabbed her sister in the chest,” the report states.
According to NJ.com, Ramirez’s relatives were in court when she pleaded guilty and wept as the proceedings unfolded.
The site reported family members told her they loved her as she was led out of the courtroom.
Hours before the fatal fight, Anna had posted an image of her with Amanda on Facebook. Both women were seen in the photo smiling with friends.
In July, Ivelisse Class, the twins’ mother, spoke to PEOPLE about the girls, recalling how the sisters were close from infancy and even shared the same bassinet. Into adulthood, the Anna and Amanda were always together, she said.
“They loved each other,” Class explained. “They were at each others’ sides when they gave birth. They took the kids out together. They drove each other to work. They were a team.”
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Class is still dealing with the pain of losing Anna.
“When you lose a child, you don’t sleep,” Class told PEOPLE. “You just wish this was a nightmare and you could wake up.”
Amanda will have to serve five years and one month of her sentence before being eligible for parole, according to NJ.com.