Fred, at the beginning.

This is from Maribeth Conway's 5-part article that appeared in the Whitman-Hanson Express, Maura's home paper. It references a press conference held on Feb 12, 2004 in New Hampshire.

After wrapping up their own search that day, Fred and Billy met with reporters in an outdoor press conference in Bethlehem, N.H. on Thursday night. "This is very unusual," Fred explained to reporters. "It's not like her to just take off."

Fred pleaded for Maura to come home. "I don't know what the matter is, or the trouble you think you might be in, but it isn't anything we can't solve," he said through the media. "It's me - you can tell me. We'll work it out until we solve it."

Three days after her disappearance, Fred was sure Maura had run away. There's no mention of foul play, that he talks about later. At that time, he's sure she's run away, even though the only real evidence anyone has at that time is that she got into a wreck, was alone for less than 10 minutes, and has not been seen again.
Even in light of the ATM withdrawal and the note to her teachers explaining she was leaving, her car has been found abandoned in the middle of the North Country. And she's missing.
What does he know that makes him so sure she's run away from the crash site? What motive would cause Maura to run away, not just from school, not just the accident, but from him as well?