Story highlights This is the fifth wave of bomb threats against JCCs, group says

Over the weekend, a second Jewish cemetery was vandalized

(CNN) Shaken workers wheeled out cribs from inside day care centers. Teachers locked hands with puzzled children and quickly led them from day school. Dismayed parents ran out of meetings and rushed to their kids.

The scenes were played out -- over and over -- at Jewish community centers and day schools in at least 12 states Monday after a series of bomb threats were called in.

In every case, police found no suspicious device. But the threats were enough to disrupt daily operations and rip apart the sense of security.

The Anti-Defamation League said 20 threats were made Monday -- in Alabama, in Delaware, in Florida. In Indiana, Maryland, Michigan.

The list goes on: New Jersey, New York, North Carolina. Rhode Island, Pennsylvania and Virginia.