Police combing a Salt Lake City home for clues on the whereabouts of missing University of Utah student Mackenzie Lueck named its owner as a "person of interest" Thursday, adding they are searching for a mattress and box spring removed from the home last week.

Lueck, 23, was last seen meeting an unknown individual around 3 a.m. on June 17 near a park in Salt Lake City after being dropped off by a Lyft driver. She hailed the ride after flying in from Los Angeles – where she had attended a funeral – and has not been heard from since.

“The owner of the residence where we served the warrant last night is a person of interest," Salt Lake City Police Chief Mike Brown said at a press conference Thursday. He added that no arrests have been made in what he says is still a missing person’s case. The homeowner, according to a detective that spoke to Fox News, will not be identified until police make an arrest.

Police first showed up at his property Wednesday afternoon -- which they described as having a "nexus to the missing Mackenzie Lueck case" -- and were spotted digging holes in its backyard earlier this morning.

Brown also said Thursday that "there was a mattress and a box spring that were given away" from the residence last week, and asked for the people who had taken the items to come forward and turn them in to investigators. He also said that multiple items of evidence were removed from the house by investigators.

Later Thursday, a box was delivered to the home. The box appeared to hold one or more parts of a bed, but police -- who were taking pictures of it -- wouldn't confirm what was inside.

The developments came after neighbors say the owner recently was burning something that let off a “strong stench.”

In the overnight hours, investigators who arrived at the home to carry out a search warrant there were seen carrying shovels into its backyard.

POLICE LOOKING INTO MACKENZIE LUECK’S SOCIAL MEDIA, ‘DATING ACCOUNTS’ AFTER DISAPPEARANCE

Aerial footage captured hours later by a helicopter belonging to news station KSL then showed police inspecting numerous, freshly-dug holes.

Brown paper bags -- presumably police evidence -- were spotted lined up in front of the home’s doorway, the Salt Lake Tribune reported. A car also was towed away by investigators.

Neighbors who spoke to the newspaper say they recently saw the homeowner burning something in his backyard and smoke from the fire was traveling into their windows.

LAST KNOWN PERSON WHO TEXTED WITH LUECK IS COOPERATING WITH POLICE

“It definitely assaulted your nose,” Joseph Peterson, who lives one block west of the home, told the Salt Lake Tribune, describing how he got home one night from work only to smell a “strong stench” in the air.

Another neighbor, Tom Camomile, described the homeowner as a person who rarely spoke to anyone else while outdoors and had turned part of the home into an Airbnb rental property.

“There are people coming and going most of the time,” he told the Salt Lake Tribune.

It’s not clear if the unknown individual that Lueck is said to have met at the park is the owner of the home or the renter.

An Airbnb listing of the property advertised "beautiful and affordable basement rooms in the heart of [Salt Lake City] with shared common area" for $27 and $30 a night.

One reviewer wrote that the host "is the kindest person, and the room is spacious enough for one or two," while another said she stayed there for two weeks before the "super kind" individual "offered to help me move."

CLICK HERE TO GET THE FOX NEWS APP

But neighbors are worried about the search, and fear something "really bad" has happened at the property.

“The K-9’s [were] here. They’ve been in the backyard. They’ve been looking in the car," Cheri Pearson told Fox News. "I told my husband ‘this is bigger than just a dope deal, or something – something really bad has happened over there.'”

Fox News' Paulina Dedaj contributed to this report.