I saw few days on TV they say he was at work. That is assuming she disappeared when they say. They aren’t saying what her timeline is. Police/FBI are being very tight lipped.
They said that she apparently got home that night, and apparently changed into work clothes the next AM
Because they don't have much to go on except speculation.
Most likely she crossed paths with a psycho who saw an opportunity and took it. Some hunter or farmer will probably stumble upon her remains. These stories rarely have happy endings.