I Can't find my backpack

As soon as I get in the house I heard my daughter Angel crying.  She was so upset because she can't find her backpack.  She been home for almost 4 hours and just realize that her backpack is nowhere to be found.

Trying to help her retrack what she did before she took off from school bus.  She was 100% sure , she was carrying her backpack.  But my mom who picked them up at the bus can't tell us either if she have her backpack w/ her.  I can't believe it not even one of them did not noticed that she lost her backpack.

We are not so worried because we are very sure that the school bus driver will keep it somewhere safe.  And Angel will get it back on Friday because tomorrow is holiday and no school.  We will make it sure to call the school as well.

This just tells me that she is not responsible enough to take care of her stuff.  I better ask her sister to double check everytime they get off from that school bus.