A bullet was found Friday morning at Lindenhurst Middle School, where earlier this week enhanced security measures were put in place because of a written threat against the school, officials said.
School officials said in a post on the Lindenhurst school district website that the bullet was found by several students on the floor in the boys locker room.
The students reported it to Principal Frank Naccarato, and the district notified Suffolk County police, the post said.
"The police have collected the bullet and have begun an investigation," the post said. "In addition, district officials have searched the surrounding area, as well as all of the lockers in the boys locker room, and have found no other evidence."
In a statement police said they "were notified and retrieved the bullet. The investigation is ongoing."
On Monday and last Friday, the school put in additional security measures and additional police were assigned to the school because a written note threatening the school was found in a boys bathroom.
The note was found Oct. 14 by a student, who told a teacher, and administrators then were notified the same day, the district said.
School officials said the threat was specifically for Monday and against the building, but declined to say more.
Superintendent Daniel E. Giordano had announced several "tentative precautions" that started last Friday and continued Monday, including the searching of bags and students limited to entering the building through two doorways.
Alison DeMaria, communications director for the Lindenhurst school district, described Monday's opening as "smooth sailing," and the school resumed its regular morning routine on Tuesday.