CASPER — Two off-campus parties held as students return to Laramie have helped spark the spread of the coronavirus there, which on Wednesday prompted the University of Wyoming to hit a five-day pause on all campus activity.

Safety measures related to COVID were not followed at the gatherings, the school said. The school’s dean of students is now conducting an inquiry into last weekend’s gatherings with the intent of pursuing student conduct proceedings. For students who hosted or attended the gatherings, that could result in being placed on interim suspension from the university and having access to the campus temporarily restricted.

“To the best of our knowledge, the vast majority of the new cases this week are related to two off-campus gatherings last weekend. That gives us some hope that we’ll be able to manage the outbreak and emerge from the pause,” said UW epidemiologist Brant Schumaker, who is directing the university’s testing program. “But this will only be possible if everyone follows the pause restrictions over Labor Day weekend through Wednesday — and then continues to follow the guidance on avoiding large gatherings, wearing face protection, practicing physical distancing and taking proper hygiene measures.”

The school had said it would move fully online, shut down campus and keep on-campus students confined to their dorm room floors if it had five positive, symptomatic cases within a single day. The school almost hit that tally Tuesday and did by Wednesday, when seven positive student tests were recorded. By Thursday evening, the school had tallied 18 positive tests of symptomatic people in three days.

While the residence halls are still far from full, students have returned to off-campus housing in recent weeks. In-person schooling had been set to start Monday for first-year students.

But all of that is again on hold due in significant part to parties, UW spokesman Chad Baldwin said Thursday. At least some of those gatherings have been held by Greek organizations on campus, he said. Part of this five-day pause will be spent investigating the role of these parties and whether any students should face disciplinary action for their participation.

“The pause is sort of intended to drill down on that,” Baldwin said. “Was that it or are there other sources now? Is there some other spread going on? We’ve done the best we can to quarantine those who’ve had close contact in those gatherings and who’s tested positive. The pause gives us the chance — ‘Alright, where is all this coming from?’”

Students in UW housing will be under a shelter-in-place order during the duration of the pause, with their movement restricted to their floor. All classes will be online — which, because in-person classes were set to start for freshmen on Monday, means a two-day delay — and nearly all employees will work from home.

As of Thursday afternoon, there were 30 active cases among UW students and staff. Four of those were students in on-campus housing, 22 were among off-campus students and four were among staff. Seventy-two students are on a 14-day quarantine — all but three of those are off-campus students, including people in two Greek life houses. Sixty-three students and staff have recovered, and the school — which is implementing rigorous and regular testing — has processed 12,862 samples.

Baldwin said that at the end of this five-day pause, UW president Ed Seidel will make a decision on whether to return to the phased reopening plan or to move the rest of the semester online. Baldwin said there was a chance Seidel could institute another pause but added it was more likely that it would be an either-or decision.

Seidel will have to weigh not just how many cases are on campus, but also the impact of ending school and then sending students right back to their home communities, in Wyoming and across the country. Baldwin said Seidel “really wants in-person” but that the decision would boil down to what’s the safest move for campus.