ROSEBURG, Ore. — The gunman who killed nine people last week during a writing class here had an uncomfortable exchange with the teacher earlier in the week, one of the survivors of the shooting at Umpqua Community College said.

The survivor, Tracy Heu, a nursing student, said she had recognized the killer, Christopher Harper-Mercer, as a student who had spoken up on another day when the teacher, Lawrence Levine, asked for the definition of a vocabulary word. When Mr. Harper-Mercer offered a response, Mr. Levine “kind of corrected Chris,” Ms. Heu, 30, said in an interview at her home this week.

Mr. Levine was among the nine killed by Mr. Harper-Mercer.

Another student in the class, Lacey Scroggins, confirmed through her father, Randy Scroggins, that Mr. Harper-Mercer had engaged with the teacher and said he was a vocal member of the class, which had begun that week.

Image Christopher Harper-Mercer Credit... via Associated Press

Ms. Scroggins, 18, and Ms. Heu are among the few survivors from Classroom 15 in Snyder Hall who have described their experiences. On the morning of Oct. 1, Ms. Heu said, she was in a center seat in the front row of the writing class when Mr. Harper-Mercer strode into the room about 10:30, smiling and wearing black clothes and a bulletproof vest.