There was a massive police response Monday on the grounds of Walter Reed National Military Medical Center in Bethesda after a report of shots fired at the facility was called in. It led to a campus lockdown and an order for those inside Walter Reed to shelter in place.
But after hours of searching, police say they found no evidence that any shooting occurred and the all-clear came just after 2 p.m.
At 10:48 a.m., Montgomery County police say a 911 caller reported hearing a single gunshot inside the Building 1 at Walter Reed National Military Medical Center.
The 243-acre campus went on lockdown as local and federal police descended on Walter Reed.
"They strategically and tactically just went floor-to-floor, office-to-office looking for any threat," said Montgomery County Police Capt. Paul Starks.
People were seen leaving the 20-story building with their hands in the air or on top of their heads.
Outside of the campus, Wisconsin Avenue was also shut down.
While all of this was going on outside, medical care inside Walter Reed went on.
"During the incident, no critical care or essential inpatient critical care lapsed during this time," said Sandy Dean, spokesperson for Walter Reed National Military Medical Center.
But as the late morning turned into early afternoon, word came that the report was unfounded.
"There is no evidence or any indication of a firearm being discharged and there are no injuries," Capt. Starks.
And just after 2 p.m., a siren sounded with a voice notifying everyone at Walter Reed the all-clear and normal operations could resume.
For the thousands who work and visit the campus, this was a tense day, but one they know could have turned much uglier.
But many who work at the hospital said they have been prepared for this sort of thing and that helped keep people calm.
"The subway manager … she was outstanding, allowed all of us to take cover behind the counter," said Denise Moore, a patient at the hospital. "We also had an off-duty cop, which sure made you feel a whole lot better. We just stayed behind there. She offered everybody water, made people comfortable. We had several elderly people in chairs."
"I don't think anyone was feeling too panicked, so the communication was good with us," said another woman who was on campus while the response happened.
The medical center was able to reopen the emergency room, but all appointments have been canceled for Monday.
Ongoing updates as they happened on Monday:
UPDATE - 2:15 p.m.
All-clear given at Walter Reed Medical Center.
UPDATE - 1:59 p.m.
Montgomery County police tweet all police operations inside Walter Reed are complete, and there is no evidence of a firearm being discharged on campus. Normal operations are expected to resume soon.
UPDATE - 1:46 p.m.
All lanes of Rt. 355 have been reopened. Still awaiting the all-clear from inside Walter Reed, but many law enforcement vehicles seen leaving the area.
UPDATE - 1:30 p.m.
Cpt. Paul Starks says the sweep of the 20-floor, high-rise building (known as Building 1) is complete, and there has been no evidence that a firearm was discharged. No injuries reported. Starks says there are no plans at this point to search any additional buildings on campus.
Starks says the initial call regarding the sound of possible gunshots was made to the dispatch center on campus, and from there, Montgomery County police were called. Officers from all five Montgomery County police districts responded, along with officers from many of their law enforcement partners around the national capital area. "All of this is protocol. No one agency has the resources to handle this by themselves," Starks told FOX 5's Tom Fitzgerald.
UPDATE - 1:25 p.m.
Montgomery Co. police tweet that all patient care at the Walter Reed facility has been suspended for today.
UPDATE - 1:12 p.m.
Montgomery Co. Police Captain Paul Starks tells reporters that there is no indication that a shot was fired at Walter Reed, and there are no injuries reported. Starks said personnel have been instructed to continue to shelter in place as their search continues.
Starks said the report of a possible shot fired came from inside the main high-rise building on campus. Police and authorities from a number of agencies are searching that building floor-by-floor, and once that search is complete, they will bring in K-9 units to search the building for the presence of any explosive devices.
Starks cautioned that there is NO evidence of any shot being fired at Walter Reed, but also said they will not leave the scene until the search is complete.
UPDATE - 12:51 p.m.
Temporary flight restrictions in place over Bethesda.
UPDATE - 12:44 p.m.
Montgomery Co. Police say Public Information Officers to meet with media shortly.
UPDATE - 12:38 p.m.
National Institutes of Health (NIH) security working with Walter Reed during investigation.
UPDATE - 12:32 p.m.
Stone Ridge School of the Sacred Heart, located near the Walter Reed Medical Center., is on lockdown as a precaution.
UPDATE - 12:26 p.m.
Metrobus (link) not serving the Walter Reed Medical Center - expect delays.
UPDATE - 12:13 p.m.
The U.S. Navy tweets security is still searching buildings on campus. Still no confirmation of any incident.
UPDATE - 12:10 p.m.
The NIH Metro station (Red Line) is still open across street from the Walter Reed campus, but the campus is locked down as police search continues.
UPDATE - 12 p.m.
Law enforcement personnel on campus escort occupants from buildings.
UPDATE - 11:42 a.m.
Campus personnel have been directed to shelter in place. Per Montgomery County Police, Rt. 355 is closed southbound at Cedar Ln. and northbound at Jones Bridge. Traffic exiting Walter Reed must make a right turn on to Jones Bridge Lane.
UPDATE - 11:30 a.m.
Montgomery County police say that they have not confirmed the initial report of a shot fired that came in around 10:48 a.m.
Gates to the campus have been closed to traffic.