At least a dozen police in camouflage SWAT gear and carrying guns arrived at the St. Rose of Lima Church. An Associated Press photographer saw police leave carrying something in a red tarp.
There was no official report from police about the threat or evacuation.
Shooter Adam Lanza, his mother and eight of the child victims attended St. Rose of Lima. It is a Roman Catholic Church with an adjacent school, which Lanza attended briefly.
It's not clear if there actually was a threat or if, like many tragedies, whether it was a hoax or the result of a community on edge.
The church hosted overflow crowds at all three morning masses Sunday.