Yale University's law school will be closed today and tomorrow after an explosion damaged an empty classroom yesterday.
Officials also say they will probably move a law school graduation ceremony scheduled for Monday to another location.
The blast, caused by some sort of explosive device, did not cause any injuries. Police are treating the incident as a crime, but have not ruled out the possibility it was an accident.
Investigators say it will take two or three days to fully process the scene. They are hoping to find evidence of whether a timing mechanism or other bomb parts were used.