Mackenzie Lueck, a 23-year-old University of Utah student, texted her parents on June 17 to let them know she had landed safely at the Salt Lake City airport, her father told Fox News. Nobody has heard from her in the week since.

According to police, Lueck landed home from a trip around 1 a.m. She then ordered a Lyft to an unfamiliar address in North Salt Lake City, The Salt Lake Tribune reports. According to friends, Lueck’s phone has been off since she went missing, her car is still at her home, and her luggage hasn’t been found. She has not shown up to work, or class, since that early morning ride.

Lueck's dad told local Fox station KTSU his daughter texted him and his wife to tell them her flight landed around 1 a.m. on Monday, June 17. Her family officially reported her missing that Thursday.

Though Lueck has been missing for nearly a week, and police are investigating her disappearance, a formal search party has not been set up, the Tribune reports.

In a press release issued by the Salt Lake City police department on Saturday, investigators said they have not “discovered any information that would lead us to believe that Mackenzie has been harmed or is in danger at this time.” In the same release, police also said “detectives are concerned for Mackenzie’s welfare.”

Lyft has been working with Utah police to help trace Lueck's last known whereabouts, the Tribune reports.

The ride share company told Fox News that the car’s route showed no irregularities, Lueck was successfully dropped off at her desired destination, and the driver began picking up more passengers immediately after her ride was complete. Authorities said they've been in contact with Lueck's apparent driver, but have not provided details of their account.

“We’ve confirmed with Lyft, the app, that’s where she requested to go, and with the driver that that’s where she did go,” Salt Lake City Police Sargeant Brandon Shearer told ABC News. Shearer said the driver and Lyft have been cooperative.

Lyft told Fox News in a statement on Sunday that they “recognize how scary this must be for those who know and love Ms. Lueck... The safety of our community is fundamental to Lyft and we are actively assisting law enforcement with their investigations.”

Lueck, who reportedly goes by “Kenzie,” is a member of the Alpha Chi Omega sorority, according to the Tribune. Her sorority sister Ashley Fine has been organizing volunteers to help in the informal search. Fine told The Salt Lake Tribune she does not know why her friend, who does not have a significant other, would have taken a ride to the address in North Salt Lake, instead of going directly to her home.

As part of the community effort to find her, Lueck's friends organized a postering event at Liberty Park in Salt Lake City on Saturday. A Facebook page with over 2,000 members has also been set up to help spread the word about her disappearance.

“Everyone thinks that there’s danger in this story,” Fine told a local abc news affiliate. “Things aren’t adding up. She had another trip planned,” Fine said. “She’s making those plans with friends and family to have plans for the future. I don’t think she would hurt herself or anything like that... If you’re in a bad situation, please reach out... We’re really concerned for you.”

Anyone with information about Lueck’s whereabouts is encouraged to contact Salt Lake City Police at 801-799-3000 and reference case No. 19-111129.

This is a developing story.