lake city. rt it is with heavy heart that i address you today. c reporter: salt lake city police chief mike brown says up until the moment swat officers lwde an arrest, he had always arld out hope that 23-year-old mackenzie lueck would be found alive. when did you know in your gut that this was no longer a missing person's case? >> i did not know until early this morning. we are filing charges of aggravated murder, aggravated kidnapping, and desecration of a body in the homicide of mackenzie lueck. the man charged is ayoola ajayi. . will not be saying the killer's name again. >> reporter: police say digital evidence proves the suspect had texted mackenzie at 6:00 p.m., hours before she boarded a flight to salt lake city. she landed at 2:00 a.m. and took d lyft from the airport to hatch park. detectives tracked his phone to the same location at 3:00 in the morning. >> the investigation shows the