Elmont Memorial High School has been placed on lockdown after a report of a suspicious person, possibly with a weapon, in the area, CBS Station WCBS reports. The lockdown was put into effect shortly after 8 a.m., in response to a 911 call. No injuries have been reported. Nassau County Police were still guarding the entrance of school more than three hours later. SWAT teams were also seen in front of the school building. A search of the school and the area is ongoing.