Ms. Mortensen described having to sleep in her mother’s bed following the murders, afraid to even close her eyes.

“If I blinked, someone might be there,” she said.

One of the enduring mysteries of the November 2022 killings has been why neither Ms. Mortensen nor the other surviving roommate, Bethany Funke, called 911 for more than seven hours after the attacks. Ms. Mortensen told investigators that she had seen a masked man moving through the house in the middle of the night but retreated back to her room. She texted her roommates and, when there was no response, hunkered down in Ms. Funke’s room until about noon, when friends came to the house and discovered the body of one of the victims.

In court on Wednesday, Ms. Mortensen did not talk about what she witnessed that night. But Ms. Funke, who wrote a statement that was read in court by a friend, described feeling guilt over not doing more, saying she had been unaware of what had taken place upstairs.

“If I had known, I, of course, would have called 911 right away,” Ms. Funke said in her statement. “I still carry so much regret and guilt for not knowing what had happened and not calling right away, even though I understand it wouldn’t have changed anything, not even if the paramedics had been right outside the door.”

Families of three victims also addressed the court during the hearing on Wednesday. Some relatives spoke directly to Mr. Kohberger, who wore an orange jumpsuit and looked at them as they spoke but did not visibly react. Several of them spoke openly about the possibility that he might face physical assault in prison.

Steve Goncalves, the father of one of the victims, Kaylee Goncalves, stood at a lectern facing Mr. Kohberger and said he would continue to avoid speaking his name and use only his initials.

“In time, you will be nothing but two initials, forgotten to the wind,” Mr. Goncalves said. “No visitors, nothing more than initials on an otherwise unmarked tombstone.”

Jazzmin Kernodle described the important moments that she had hoped to experience with her sister, Xana Kernodle, another one of the victims.

“Xana didn’t get the future she deserved,” she said. “She won’t be the maid of honor at my wedding, the cool aunt to my future children. I’ll never hear her laugh or see her light up a room ever again, but I will carry her with me for the rest of my life.”

The family of Ethan Chapin, the only male victim, said they would not be attending the sentencing hearing.

Mr. Kohberger’s mother was in the courtroom and watched as the victims’ relatives and friends spoke, shuddering at times and in one instance putting her head in her hands.

When Kim Cheeley, the grandmother of victim Madison Mogen, addressed the court, she included a sympathetic reference to Mr. Kohberger’s family.

“My heart aches for the kids’ roommates and the families of the other victims, and also the family of the perpetrator,” Ms. Cheeley said.

Families of the victims have expressed different views of the plea agreement, with some saying they had hoped Mr. Kohberger would be sentenced to death, and others expressing relief that they could avoid a lengthy and grisly trial.

The plea deal has also left many lingering questions about the case unresolved, with Mr. Kohberger admitting to the murders but not shedding any light on his motive.

Ms. Goncalves’s older sister, Alivea Goncalves, pressed Mr. Kohberger in her statement in court to provide answers.

“Where is the murder weapon?” she asked. “What were Kaylee’s last words?”

“Do you feel anything at all?”