The freshman building has essentially remained unchanged since a gunman opened fire inside Marjory Stoneman Douglas High School on Feb. 14, 2018, sending students and teachers fleeing for their lives.

Laptops are still cracked open on desks where students’ essays remain unfinished. A copy of “To Kill a Mockingbird” was in one classroom near assorted teddy bears, candy hearts and other forgotten Valentine’s Day gifts. But alongside the signs of what began as an ordinary school day in Parkland, Fla., were trails of shattered glass, bullet holes and blood where 14 students and three staff members were killed.

A dozen jurors and 10 alternates made a rare visit to the scene of the mass shooting Thursday in the sentencing trial of convicted shooter Nikolas Cruz. The 23-year-old faces either the death penalty or life in prison after pleading guilty in October to 17 counts of murder and 17 counts of attempted murder.

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The jury, along with Circuit Judge Elizabeth Scherer, attorneys and journalists, walked through the same hallways and classrooms in the three-story building as Cruz did four years ago. The building has remained closed off to the public behind a 15-foot chain link fence covered in privacy mesh — but prosecutors hope the scene inside will make the case that Cruz should be sentenced to death.

Reporters described the crunch of shattered glass underfoot and the sight of dried blood — contrasted by deflated balloons and decaying rose petals left behind in the students’ rush to escape. On the third floor, where six people died, “the blood in the hallway is something that I would never wish on people to have to see,” said South Florida Sun Sentinel reporter Rafael Olmeda.

“It was disturbing on a number of levels,” Olmeda said in a pool report interview. “What we saw was the end result of children who are in the middle of an average day having a wonderful time, and all of a sudden, a nightmare erupts.”

In Dara Hass’s ninth-grade English class, where Alyssa Alhadeff, Alaina Petty and Alexander Schachter died, students had been writing before the attack.

“We go to school every day of the week and we take it all for granted,” one student wrote. “We cry and complain without knowing how lucky we are to be able to learn.”

Six bullet holes peppering a window on the third floor showed Cruz’s attempt to fire at the students fleeing outside. Blood could still be seen where geography teacher Scott Beigel fell while ushering students into a classroom.

In an alcove outside the bathroom where Joaquin Oliver died, a pool of blood and bullet holes in the wall indicated how close Cruz was when he shot the 17-year-old, who helplessly held up his hands. The heart-shaped Valentine’s card he carried was left covered in blood. Oliver would have been 22 on Thursday.

“We don’t just see a large pool of blood where Joaquin Oliver died,” Olmeda said. “We see a large pool of blood where, we know from testimony, Joaquin Oliver sat and waited, knowing he was next to be shot.”

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Reporters said the jurors did not reveal signs of emotion during the visit, although one appeared to put her arm around another in a supportive gesture.

Trial consultant Robert Hirschhorn, who was not involved in the case, said it is “extraordinarily rare” for a judge to allow a site visit in any criminal trial. This marks the first time in recent history a judge has allowed such a visit when considering a punishment, he said.

“Site visits always leave indelible and unforgettable impressions with jurors,” Hirschhorn said.

In Florida, a death penalty requires a unanimous recommendation by the jury. Cruz’s defense team, which has pushed for a life sentence based on Cruz’s difficult upbringing and mental health issues, will make its opening statement after next week’s recess.

Since the trial began on July 18, jurors have been exposed to graphic videos, photos and audio clips. They have listened to medical experts describe the destructive injuries caused by Cruz’s AR-15-style weapon. Now, they have witnessed carnage suspended in time.

Thursday also brought the last day of victim-impact statements, during which the loved ones of 17-year-old Helena Ramsay, 15-year-old Peter Wang and 49-year-old athletic director Christopher Hixon described how their lives had been upended.

Clad in a suit with a burgundy bow-tie, Hixon’s son Corey told the court that he missed the Saturday runs to Dunkin’ he took with his father, a Navy veteran.

With three gut-wrenching words, Corey brought people in the courtroom to tears — including members of Cruz’s defense team.

“I miss him,” said Corey, leaning into his mother for a hug and breaking into a sob.