LOWER MACUNGIE TWP., Pa. -

The discovery of an empty shell casing prompted the lockdown of a school in Lehigh County on Wednesday.

The casing was found inside Lower Macungie Middle School in Lower Macungie Township, according to a spokeswoman for the East Penn School District.

Pennsylvania State Police and district administrators investigated the discovery, and police determined that there was not threat to student safety.

The lockdown was lifted in time for classes to resume before dismissal.