A 15-year-old boy displayed the knife at his bus stop and was met by staff members as he exited the bus at Sachem High School North in Lake Ronkonkoma, according to Suffolk County Police.
The knife was recovered, and police were notified.
The teen was arrested and charged with criminal possession of a weapon.
A further investigation by Suffolk County PD Fourth Precinct Crime Section officers determined that the teen had previously been threatened by another 15-year-old boy in July.
That teen was also arrested and charged with aggravated harassment.
Both teens were released to the custody of their parents and will be arraigned in Family Court on a later date.
Click here to follow Daily Voice Rocky Point and receive free news updates.