MONESSEN, Pa. » A Pennsylvania school district superintendent says five middle school students were mistakenly handed word search puzzles based on "Fifty Shades of Grey" with such terms as "leather cuffs" and "spanking."

The Valley Independent reports Monessen Schools Superintendent Leanne Spazak issued a statement Thursday apologizing and saying the puzzles were "mistakenly and unknowingly" put in a stack of worksheets given to five students Monday.

Spazak didn’t say how that happened or whether any employees were disciplined.

A staff member collected the sheets from the five students once they began sniggering at words like "bondage," ”submissive" and even more explicit terms.

One student kept a copy, however, and posted it on social media, which prompted parent complaints and media inquiries.