(NewsNation) — Classes resumed at the University of Idaho Monday morning after the holiday break and more than two weeks after the stabbing deaths of four students. With no clear suspect, no weapon and little to no answers, the college town of Moscow is on edge.

NewsNation’s Brian Entin spoke to students on campus Monday who said there are noticeably fewer people around following the Thanksgiving break. Despite an increased police presence, many are opting to do classes online instead of returning in-person and others said they are planning to stay inside after dark.

Monday afternoon, Moscow Police issued a news release ruling out two more theories. They say a February death in town was an overdose and had no relation to the four stabbings. They also said reports of a red Mustang being part of the murder investigations are inaccurate.

Authorities say so far they have sifted through 1,000 tips related to the deaths and have warned against speculation that has stoked community fears in the weeks since the deaths.

Investigators said over the weekend there have been more than 488 digital media submissions by communities to the FBI link, and 113 pieces of physical evidence have been collected in the investigation and taken to the Idaho State Police crime lab.

The four University of Idaho students found stabbed to death in an off-campus rental home Nov. 13 were Ethan Chapin, 20, of Conway, Washington; Madison Mogen, 21, of Coeur d’Alene, Idaho; Xana Kernodle, 20, of Avondale, Arizona; and Kaylee Goncalves, 21, of Rathdrum, Idaho.

They were all close friends, as well as members of fraternities and sororities. Chapin was dating Kernodle, who was roommates with Mogen and Goncalves.

NewsNation executive producer Paige Lobdell emphasized the stabbings’ impact on the community in a Twitter Spaces conversation with NewsNation’s Brian Entin and former FBI Agent Jennifer Coffindaffer over the weekend.

“We’ve talked to parents who are like, ‘I called my kid up and I said you’re coming home for Thanksgiving early.’ I mean, this is the first murder in this town in I think they said seven years,” Lobdell said.

Since Nov. 13th, local authorities say they have received 78 calls for unusual circumstances and 36 welfare check requests.

Former FBI special agent Tracy Walder says the fears are not misplaced and there is a chance the killer could be in town.

“I’m very glad that the University of Idaho did offer an online option, because I’m certain that is probably unsettling to their students to come back, although some may be comfortable in coming back,” Walder said on “Morning in America.” “I think that the killer may actually still be around. Because I do think that the killer may have been someone known to these victims, and is probably starting to feel a little bit more and more confident that they’re not going to be caught.”

You can watch the full interview with Walder in the player below.

The University of Idaho is hosting candlelight vigils on Tuesday at 5 p.m.local time to honor the memories of the four students. One will be held on the Moscow campus and another at the University of Boise.

Idaho Gov. Brad Little has directed up to $1 million in state emergency funds for the ongoing investigation, police said.

This story is developing. Refresh for updates.

The Associated Press contributed to this report.