This case is just heart wrenching....a darling girl walking innocently to school... and then?
It is strange that "the friend" wasn't mentioned earlier, but here is what I think, (IMO), may have happened.
The friend came over and the girls did indeed walk out the front door and leave together - but they either got in a tiff or her friend ran ahead to get to school early and/or saw someone ahead of them that she caught up with leaving Jessica to walk on her own/assuming she would make it to school "fine", just like any other day. Girls in grade 5 are often very flighty and moody - maybe the friend didn't want to walk as slowly as Jessica or stop at the park (etc) and went on ahead- this could explain why LE said they had a witness that Jessica was known "to be on her way to school". The poor friend is probably traumatized
Being ahead of Jessica, she would not have witnessed what happened, and if they weren't in the same class may not have even been aware that her friend was missing.
I remember reading earlier that Jessica called a friend from a blocked # at around 7:30 a.m. to see if another friend she usually met up with at the park was walking ,but he was getting a drive that day - maybe the girl she left the house with just assumed Jessica still had someone to walk with... ?
In any case my thoughts and prayers are with Jessica's family and friends...praying for a safe return.