Yes actually, I posted this back on June 19th....
CSI Season 5 Episode 3 - Harvest
Woman (with lots of red hair, actually) goes to school to pick up her child. Very impatiently waiting, honking the horn.
Teacher comes over and asks if something is wrong.
Mother asks what is taking the child so long as they have a doctor's appointment.
Teacher says child is not at school.
Mother says she has to be there, she saw her leave for school that morning.
Teacher says she hasn't been in any of her classes that day.
It is alleged that the child was abducted from outside a convenience store while she was with her sister.
They find the child's body and determine she was dead before she was reported kidnapped.
They are suspicious of the mother apparently liking the other children more than the murdered child. Possibly only using the murdered child to help save her favorite child, the son who had a terminal illness.
The blanket she was wrapped in match fibers in the house. The boot prints match the father's boots.
It ended up being the brother who killed her to save the girl from having to keep "saving" him, then the parents covered it up and the sister faked the kidnapping.
I tried to find this somewhere else, but couldn't. I was really only looking for a clip, but this is the whole episode. The first few minutes covers the school and reported abduction part.
http://www.fanpop.com/spots/csi/videos/75207/title/season-5-episode-3-harvest?part=1
It is: CSI Season 5 Episode 3 - Harvest, If anyone finds it somewhere that will play faster than this link...or has a shorter clip let me know. I'm pretty sure it is just regular CSI because it doesn't say otherwise. But someone who is a avid fan will be able to tell from the characters and I can edit if it's Miami or something.