A report of a person with a gun near Hampton Bays High School on Thursday morning prompted a lockdown that Southampton Town police later determined was sparked by a student playing the popular senior-year game “senior assassin."

Police say a resident called 911 around 7:20 a.m. after seeing a teenage male get out of a vehicle holding what appeared to be a long gun near Argonne and Wakeman roads. Officers searched the area, and the high school was secured as a precaution.

Police later found the teen, the vehicle and the weapon, which turned out to be a toy water gun used in the off-campus game.

“Senior Assassin,” a tradition at many schools, assigns students “targets” and tasks them with eliminating each other using water guns until only one player remains.

In emails to families throughout the morning, the district first warned of nearby police activity, then confirmed the suspected threat was “resolved and unfounded.”

No arrests were made.

School officials held an assembly with seniors and School Resource Officers to address the risks associated with the game. They also informed families that toy guns can easily be mistaken for real weapons, prompting a “significant response” from law enforcement.

The district encouraged parents to speak with their children about making safe decisions during senior-year activities.