LANSING, Mich. (AP) — Michigan State University professor Marco Díaz-Muñoz is still haunted by what he witnessed last Monday night, when a gunman entered his classroom in Berkey Hall, killing two of his students in what he describes as “12 minutes of terror.”

“Those images haunt me. The images of those two girls,” Díaz-Muñoz told The Associated Press.

Arielle Anderson and Alexandria Verner, both juniors, would die that night, Feb. 13. The suspected gunman, Anthony McRae, would shoot six more students during the rampage in two campus buildings. Brian Fraser also would die. Five others would suffer critical gunshot wounds.

On Monday, Díaz-Muñoz and others are set to return to class. The university confirmed Friday in an email to students and staff that campus operations would resume, even as officials have faced pressure to delay the return. There will be no classes for the rest of the semester in Berkey Hall, where two students died, for the rest of the semester.

Díaz-Muñoz said the university offered to have another professor to teach through the end of the semester. While he has yet to make a final decision, his plan is to go back next week and teach.

“On one hand, I want to forget it all. But then on the other hand, I think I need to help my students pick up the pieces,” Díaz-Muñoz said. “I think I need to help my students build a sense of meaning.”

Some in the community, however, aren’t ready for the rapid return. The editorial board of The State News, the student newspaper, wrote Thursday that they wouldn’t attend class next week, either in person or online. More time was needed to heal, the students wrote.

In the days following the shooting, students across campus were seen packing their belongings to leave East Lansing with all activities shut down for 48 hours and no classes until at least Monday. A petition demanding hybrid or online options for students received over 20,000 signatures as of Saturday. Michigan State has about 50,000 students, including 19,000 who live on campus.

Díaz-Muñoz understands that some students won’t be ready to return, saying that some will still have “the fear of looking over their shoulder and looking out the window, at the doors.”

“There are some kids in my class that are graduating this semester. And they need this horrific nightmare to have a better ending than the way it ended on Monday,” Díaz-Muñoz said.

In an email sent out to faculty Friday, the university said that all students will be given a credit/no credit option this semester, which allows students to receive credit for all classes without it impacting their overall grade point average. The email, written by interim Provost Thomas Jeitschko, asked all teachers to “extend as much grace and flexibility as you are able with individual students, now and in the coming weeks.”

“We are encouraging empathy and patience and an atmosphere for all to recover at their own pace,” Interim President Teresa Woodruff said Thursday.

Four wounded students remain in critical condition at Sparrow Hospital, a hospital spokesman confirmed Saturday. One had been upgraded to stable condition on Thursday.

Dozens of people have died in mass shootings so far in 2023. In 2022, there were more than 600 mass shootings in the U.S. in which at least four people were killed or injured, according to the Gun Violence Archive.

The shootings at Michigan State happened Monday during evening classes at Berkey Hall and nearby at the MSU Union, a social hub where students can study, eat and relax. Students across the vast campus were ordered to shelter in place for four hours — “run, hide, fight” if necessary — while police hunted for Anthony McRae, 43, who eventually killed himself when confronted by police not far from his home in Lansing.

Police said he left a note with a possible motive but have not said what it was. He was the lone shooter and had no connection to the victims or to Michigan State as a student or employee, they said.

Díaz-Muñoz describes hearing “explosions” outside his class before a masked man appeared in the doorway of Room 114 and began open firing. Students hid behind desks and chairs before breaking windows to escape.

After “one to two minutes” of shooting, the gunman turned around and left, leaving behind “destruction and death in my classroom,” said Díaz-Muñoz.

For Díaz-Muñoz, the terror didn’t end as abruptly. The carnage that occurred in his classroom was “something you saw in a movie,” he said.

Díaz-Muñoz says he has taken prescription medication as a way to force himself to sleep, only emerging from his room “for a bowl of soup.”

The assistant professor said that he is sharing his story in hopes of bringing about gun reform.

“If the lawmakers and the senators saw what I saw, instead of hearing in the news one more statistic. If they had seen those girls and the pools of blood that I saw, the horror we lived, they would be shamed into action,” Díaz-Muñoz said.