Lincoln police report 74-year-old Ervin Martin and 69-year-old Janice Ortiz died Saturday night in the fire.
Firefighters first responded to a medical emergency, but found the mobile home filled with smoke and flames when they opened the door of the residence near the intersection of Interstates 80 and 180 in northwest Lincoln.
Investigators for the Lincoln Fire Department determined a lit cigarette started the fire. Both used oxygen machines to breathe. While authorities believe the two died from smoke inhalation and burns, autopsies will be performed to confirm the cause of their deaths.
Marion Bailey, KLIN, contributed to this report.