Sosefina Amoa arrived in the District from the Pacific island nation of Samoa on Oct. 5, completing a 7,000-mile journey to become a Catholic nun with the Little Sisters of the Poor. What neither she nor the nuns knew, she later told police, was that she was pregnant and near full-term.

According to court papers, Amoa, 26, told detectives that when the 6-pound 2-ounce baby was born in her bedroom Oct. 10, she was afraid the nuns in the convent would hear his cries. D.C. police said she smothered the newborn — called Baby Joseph — with a black wool garment, and a day later, with the help of a nun, she took the body to a hospital in a suitcase.

Amoa was arrested Wednesday and charged with first­­­-degree murder after the medical examiner ruled the death a homicide by asphyxiation. Her scheduled arraignment in D.C. Superior Court on Thursday was postponed while she receives hospital care. Her attorney, Judith Pipe of the District’s Public Defender Service, declined to comment.

Many questions remain about the case as authorities look into Amoa’s long path to the District and her acceptance as a postulant, or student of doctrine and prayer life. Little Sisters of the Poor, a religious order with missions around the world, operates nursing homes and assisted-living residences for the impoverished elderly.

The order, which started in France in 1839, operates more than 100 apartments and rooms on seven acres in the 4200 block of Harewood Road NE, across the street from Catholic University. The order came to the United States in 1869, establishing its first house in Baltimore, and now has provincial headquarters in the suburb of Catonsville, Md., from where it oversees missions in the District and in seven states.

“It’s really a tragic situation,” said Mother Alice Marie Monica, who runs the province. “We are praying for everyone that is involved.” She would not comment further.

Police said they have not found any relatives of Amoa’s in the United States. Attempts to reach people who knew her in Samoa were unsuccessful. Little Sisters of the Poor has a mission in Samoa whose mother superior could not be reached for comment.

Sister Patricia Wittberg, a sociologist at Indiana University-Purdue University Indianapolis, said the order operates top-notch care facilities for the elderly, and she described it as “long-established, very respected and somewhat traditional.” She said that it would be difficult for a woman to be admitted as a postulant in the United States without going through rigid medical tests but that the same standards might not apply in other countries.

According to an affidavit filed with the arrest warrant in Superior Court, Amoa told detectives that she had not known she was pregnant. She told police that she started bleeding Oct. 9 and thought it was her menstrual period. She said that the boy was born shortly after 11 a.m. the next day, according to the court papers, and that the infant fell to the floor.

At first, the suspect told police, she lay down with the child, who cried for two or three minutes and then stopped suddenly, according to the court papers. She told police that she became afraid the nuns would hear the baby and find out that she had lied to them about sexual activity.

“She said that she placed a black wool garment over the child’s nose and mouth and applied pressure with her hand for two to three minutes,” police wrote in the affidavit. “The mother said that prior to placing the wool garment over the child’s nose and mouth, the child was breathing and had cried. The mother said that after she removed the garment from the child’s nose and mouth, the child was not breathing and she knew the child was dead.”

Amoa told police that she put the body on her bed and stayed with it until the morning of Oct. 11, according to court papers. She said she considered putting the body in the trash but decided to tell a nun about the child. First, she told the nun that she had found the boy outside, police said, then she admitted to giving birth to him.

The unidentified nun told police that she “picked up the child” and realized that it was dead, according to court papers. She “obtained a small black luggage bag which was used to transport the child to the hospital.” Police said doctors at the Providence Hospital emergency room immediately pronounced the infant dead. The baby had been wrapped in flowered clothing and the wool garment that allegedly had been used to smother him.

Michelle Boorstein and Jennifer Jenkins contributed to this report.