I think I know where your sweater is Lu...

A well known verse:

And in that dreadful place

Those spooky empty pants and I

Were standing face to face.

I yelled for help. I screamed. I shrieked.

I howled. I yowled. I cried.

Oh! Save me from those pale green pants

With nobody inside.

-Dr. Seuss

The only likely explanation. They ran off with the pants and are now somewhere south of Picacho Peak.