Salt Lake Police 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", however the college student's friends and family are increasingly concerned.
Ashley Fine, one of Lueck's friends, told The Salt Lake Tribune that Lueck's phone has been off since last Monday.
Currently, police are investigating her disappearance but have not searched her Lyft destination as there is no evidence she stayed there according to Brandon Shearer from the Salt Lake City Police. The Lyft driver has been cleared as a potential suspect, police said.
"Nothing suggests she is in trouble other than we haven't heard from her", Wilking said.
"The university's dean of students has spoken with Mackenzie's family to offer support and to express the campus community's shared hope for her safe return". The Lyft driver told detectives that another person with a vehicle was waiting for her. Who did MacKenzie meet in North Salt Lake City?
Lueck's cat and auto remain at her house.
"We are all anxious and looking out for you 24-7, I can not sleep at night knowing you are out there", said Kennedy Stoner, a friend of Lueck, during a news conference Sunday.
Kennedy Stoner, a sorority sister, said it was "very unlike" Lueck not to check in with her.
'We're not disclosing it, we're trying to maintain the integrity of what may become a criminal investigation, ' he said. "We're just being hopeful right now".
Detectives were interviewing friends and acquaintances, searching areas she frequents and scouring her social media accounts for any clues, Doubt said.
"Lueck is described as being 5'6" tall and 120 pounds with medium length blonde hair and brown eyes.