The woman who killed her newborn son while she was studying to become a nun at a Northeast Washington convent was sentenced to four years in prison Friday.

Sosefina Amoa, 26, originally from Samoa, pleaded guilty in February to voluntary manslaughter in the Oct. 10 death of her newborn son. Amoa admitted covering the baby’s face and mouth with a sweater, saying she was fearful his cries would alert the nuns. She said she did not know that she was pregnant before she gave birth.

“I am very sorry,” Amoa said in court, wearing a D.C. jail jumpsuit and her wrists and ankles in shackles. “I ask for forgiveness from my humble heart. I did not know what to do. I could not think straight.”

Prosecutors have alleged that she hid her pregnancy and then killed the infant because she feared she would be barred from the convent and sent back to Samoa. Amoa and her attorney say she accidentally smothered the baby amid the shock and pain of childbirth.

Judge Robert E. Morin said he thought that Amoa was in “denial” about her pregnancy and that she was in a “complicated psychological state.”

“I don’t think we’ll ever know what actually happened,” he said. But he added, “It’s hard to think of a more vulnerable victim than a child.”

Friday’s sentencing was emotional. At one point, Amoa began sobbing loudly and was comforted by her attorney and a Samoan interpreter. She was escorted out of court for about 10 minutes before the hearing could continue.

Amoa came to Washington in October to study with the nuns of the Little Sisters of the Poor. Five days after her arrival, she went into labor during a prayer meeting with the nuns, left the meeting and returned to her room, where she gave birth.

Amoa’s attorney, Judith Pipe of the D.C. Public Defender Service, tried to persuade the judge either to release Amoa or order her deported to Samoa so she could return to her family.

“She will spend the rest of her life grieving the loss of her son,” Pipe said. “She will live a life of grief and shame.”

But Assistant U.S. Attorney Cynthia Wright requested five years of prison time for Amoa.

“Good people make bad mistakes and some of those mistakes are criminal. She consciously killed her son, she held his nose and suffocated him,” Wright said.

Wright held up a poster-size autopsy photo of the baby, named Joseph by one of the nuns. The picture showed the baby’s face, with red bruises on his temple and nose.

Wright reminded the judge that Amoa admitted to police that she held the sweater over the baby’s face for about two to three minutes. The prosecutor then requested a two-minute moment of silence to illustrate the amount of time she says Amoa smothered her baby. Pipe objected, calling Wright’s move “theatrics.” Morin allowed the demonstration.

Two nuns from the convent, wearing white habits, sat in the courtroom. One wiped tears from her face.

After the hearing, one of Amoa’s sisters, Siniva Kelsall, who flew in from New Zealand, was allowed to keep the photo of her nephew. Kelsall held it close to her body as she walked out of the courtroom.