Others weren't as fortunate. Parents of students in the classroom said the gunman shot one after saying he could save his life by begging. Others were killed after being told to crawl across the floor.
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Shooter Christopher Sean Harper-Mercer later killed himself as officers arrived, Douglas County Sheriff John Hanlin said Saturday.
Authorities have not disclosed whether they have an envelope or package from Harper-Mercer. However, a law enforcement official said a manifesto of several pages had been recovered.
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Bonnie Schaan, the mother of 16-year-old Cheyeanne Fitzgerald, said she was told by her 16-year-old daughter that the gunman gave someone an envelope and told him to go to a corner of the classroom.
Harper-Mercer said the person "'was going to be the lucky one,'" Schaan told reporters outside a hospital where her daughter's kidney was removed after she was shot.
Relatives of other survivors also said Harper-Mercer gave something to a student in the class.
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Pastor Randy Scroggins, whose 18-year-old daughter Lacey escaped without physical injuries, said she told him that the gunman called to a student, saying "'don't worry, you're the one who is going to survive.'"
Harper-Mercer then told the student that inside the shooter's backpack was "all the information that you'll need, give it to the police," Scroggins said, citing the account by his daughter.
Scroggins also said his daughter heard the gunman tell one victim he would spare that person's life if the student begged then shot the begging victim anyway.
Lacey Scroggins also spoke about students being ordered to crawl to the middle of the room before being shot.
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Pastor Scroggins said his daughter survived because she was lying on the floor and partially covered by the body of a fellow student. The gunman thought Lacey Scroggins was dead as well, stepped over her and shot someone else.
Janet Willis said her granddaughter Anastasia Boylan was wounded in the Thursday attack and pretended to be dead as Harper-Mercer kept firing, killing eight students and a teacher.
Willis said she visited her 18-year-old granddaughter in a hospital in Eugene, where the sobbing Boylan told her: "'Grandma, he killed my teacher!'"
Boylan also said the shooter told one student in the writing class to stand in a corner, handed him a package and told him to deliver it to authorities, Willis said.
The law enforcement official who disclosed the existence of the manifesto did not reveal its contents but described it as an effort to leave a message for law enforcement.
The official is familiar with the investigation but was not authorized to disclose information and spoke on the condition of anonymity.
The official said the document was left at the scene of the shooting but wouldn't specify how authorities obtained it.
Boylan, a freshman at Umpqua Community College, also told her grandmother the gunman asked students about their faith.
"If they said they were Christian, he shot them in the head," Willis said, citing the account given by her granddaughter.
However, conflicting reports emerged about Harper-Mercer's words as he shot his victims.
Stephanie Salas, the mother of Rand McGowan, another student who survived, said she was told by her son that the shooter asked victims whether they were religious but did not specifically target Christians.
Her son said the shooter had people stand up before asking, "'Do you have a God? Are you Christian? Do you have a religion?'"
Salas said it was like telling the victims "you're going to be meeting your maker."
Salas said the gunman told victims "'this won't hurt very long'" before shooting them.
Law enforcement officials have not given details about what happened in the classroom. However they released a timeline that shows police arrived at the scene six minutes after the first 911 call and exchanged gunfire with the shooter two minutes later.
Harper-Mercer was enrolled in the class but officials have not disclosed a possible motive for the killings. In a statement released by authorities, his family said they were "shocked and deeply saddened" by the slayings and that their prayers went out to the families of those who died and were injured.
Harper-Mercer's father, Ian Mercer, told CNN Saturday he is struggling to understand how and why the shooting happened and that he was stunned to learn his son had accumulated so many guns.
He said the law should be changed because the attack would not have happened if his son had not been able to get guns.
The dead ranged in age from 18 to 67 and included several freshmen. They were sons and daughters, spouses and parents. Nine other people were wounded in the attack in Roseburg, a rural timber town about 180 miles south of Portland.
Harper-Mercer wore a flak jacket and brought at least six guns and five ammunition magazines when he went to the campus that morning.
Oregon's top federal prosecutor said the shooter used a handgun when he opened fire on classmates and had stashed a rifle in another room but did not fire it.
Several years ago, Harper-Mercer moved to Winchester, Oregon, from Torrance, California, with his mother Laurel Harper, a nurse.
At an apartment complex where Harper-Mercer and his mother lived in Southern California, neighbors remembered him as a quiet, odd young man who rode a red bike.
The Army said Harper-Mercer flunked out of basic training in 2008.
Harper-Mercer's social media profiles suggested he was fascinated by the Irish Republican Army and frustrated by traditional organized religion.
He also tracked other mass shootings. In one post, he appeared to urge readers to watch the online footage of Vester Flanagan shooting two former colleagues live on TV in August in Virginia, noting "the more people you kill, the more you're in the limelight."
ABC7 News reporter Wayne Freedman is in Roseburg. You can see his reports during our evening newscasts or follow him on Twitter and Facebook for the latest updates.
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