I am going by what Elaine Redwine told Nancy Grace
<snipped>
GRACE: Everyone, taking your calls is Dylan`s mother. Now, Ms. Redwine, was -- did there come a time when you learned that Dylan was missing? How did that happen?
REDWINE: Well, his dad texted me at around, oh, 4:30. Maybe it was closer to 5:00 on Monday. And I texted him back. You know, it was like, Well, we should call the sheriff. So I went ahead and I actually called the sheriff that day.
I don`t know if Mark had called the sheriff that day, either, but I called the sheriff right after I got the text from Mark.
http://transcripts.cnn.com/TRANSCRIPTS/1212/03/ng.01.html