The panties are described in the autopsy:
" Beneath the long underwear are white panties with printed rose buds and the words "Wednesday" on the elastic waistband. The underwear is urine stained and in the inner aspect of the crotch are several red areas of staining measuring up to 0.5 inch in maximum dimension."
Please note, there is NO evidence she wet the bed. This is the crime scene photo of her bed. A urine stain in the hall in the basement indicated she wet herself there, just outside the windowless room where her body was found.