Police searched a Salt Lake City house Wednesday night as part of the investigation into a missing University of Utah student. Mackenzie Lueck hasn't been heard from since a Lyft driver dropped her off at a park outside the city last week.

Salt Lake City Assistant Police Chief Tim Doubt told reporters that police served a search warrant on the house after developing leads in the case. He didn't provide details about what led authorities to the house in the city's Fairpark neighborhood.

"Obviously we are treating this with a high degree of care and caution as it is an open case," Doubt told reporters. "Given the nature of this case, we just don't want to make any mistakes. We will continue to follow leads until this is resolved."

Get Breaking News Delivered to Your Inbox

Doubt wouldn't say whether anyone who lives in the house was being questioned. "If they live here, of course they're part of the investigation because we're serving a search warrant on their house," he said.

Lueck, 23, flew into Salt Lake City's airport early on June 17 after attending a funeral in California. A Lyft driver dropped her off at a park in North Salt Lake at around 3 a.m., and the driver told police she got into another vehicle driven by an unknown person.

Police have asked the person driving the other vehicle to step forward. CBS News correspondent Jonathan Vigliotti reported that purported surveillance cameras at the park aren't real and are there to deter crime.

Doubt said Wednesday night a tip line would continue to operate. "We ask that anyone who knows anything to please call," he said.

The phone number for the tip line is (801) 799-4420.