Law enforcement officers from several agencies descended on Walter Reed Medical Center in Bethesda, Md., on Monday after a report of a single round of gunfire being heard on campus.
The call of the single shot came in just before 11 a.m. local time, Montgomery County police officials told CBS affiliate WUSA in Washington, D.C.
The Montgomery County Police Department announced at around 2 p.m. that the investigation into the report was complete and no evidence of a shot being fired was found.
WUSA reports that a Walter Reed employee tweeted that they were under a "code white." Workers were sheltering in place, the U.S. Navy said late Monday morning.
Walter Reed was the U.S. Army's flagship medical center until 2011, when officials decided to consolidate its operations with the National Naval Medical Center in Bethesda, Md., and a hospital at Fort Belvoir, Va., to save money.
The storied hospital, which opened in 1909, was scarred by a 2007 scandal about substandard living conditions on its grounds for wounded troops in outpatient care and the red tape they faced. It led to improved care for the wounded, at Walter Reed and throughout the military. By then, however, plans were moving forward to consolidate Walter Reed's operations.