All-clear at three of four evacuated Harvard buildings after bomb scare

Cambridge, Massachusetts: Harvard University has reopened a third building that was evacuated because of a report of possible explosives on campus.

Students have been told that they may return to the classroom building. Harvard Yard has also re-opened.

Two other buildings, a dorm and another classroom building, reopened earlier. A fourth building, the school's Science Center, remains closed.

A search has yet to turn up any explosives.

An alert went out shortly after 9 a.m. Monday telling students at the Ivy League school outside Boston to leave the four buildings.

It's exam time at Harvard and some students were just about to start finals when the alert went out.

The FBI is investigating along with Cambridge and university police and other agencies.