Authorities identified the man suspected of killing Lueck as Ayoola Ajayi, 31. He was arrested June 28 on suspicion of aggravated murder, aggravated kidnapping, obstruction of justice and desecration of a body in connection to Lueck's disappearance, police said.
Brown told reporters last week that Ajayi met with Lueck at a park that she traveled to after leaving Salt Lake City International Airport early on June 17. He was the last person known to have contacted Lueck, Brown said. The chief added that records showed her cellphone was no longer being used starting around 3 a.m. on June 17.
It was not immediately clear how Ajayi and Lueck knew one another, but police said they had communicated electronically the day before she disappeared.
Neighbors told police they saw Ajayi using gasoline to burn items in his backyard on June 17 and 18. Authorities previously said some of Lueck's charred remains and personal belongings were found in his backyard in Salt Lake City.
As of Friday, formal criminal charges have yet to be filed against Ajayi, KSL-TV reported. Salt Lake County District Attorney Sam Gill said authorities continue to investigate the case and expect to file charges by next week.
Authorities continue to investigate.
The Associated Press contributed to this report.
Police: Man Accused of Murder, Kidnapping of Missing Utah Student MacKenzie Lueck