Police said there were no injuries and the investigation was continuing.
The school's regular dismissal time is 2:15 p.m. and motorists had lined up in Hillside Drive for hours waiting for the students to be dismissed.
Police said it was not a bomb threat and that they will be holding a 5 p.m. press conference on the situation.
The Greenwich Schools also issued the following guidelines for Wednesday: .
- Transportation will be provided for students, an parents/guardians may now pick up students at the school.
- After school activities are canceled for the high school, EXCEPT for the Choral Concert, which will proceed as scheduled Wednesday night.
- Continuing Education classes will proceed as scheduled.
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