Joe Levine, executive director for external affairs at the Teachers College, said the building, which is open around the clock, is accessible only to those with a Teacher's College ID card or other credentials.

CNN: Police probing noose incident review Columbia surveillance video

The swarm of runners nearing the finish line as the clock ticked toward 3 in the afternoon included a medical supply salesman, a teacher's aide, a financial analyst in her 55th marathon, and a cop who would become the last recorded finisher of the 117th Boston Marathon.

NPR: The Finish Line: What The Bombing Was Like