FALLS CHURCH, Va. - There were some tense moments in Fairfax County as police were called to an office building for a report of an active shooter. However, it turned out to be a false alarm and someone was running a drill.
For about 45 minutes Thursday afternoon, workers inside the building at 5109 Leesburg Pike thought there was an active shooter inside.
"An email went out that was initially to be a drill internally to one of the tenants inside [the building]," said Fairfax County Poolice Officer Roger Henriquez. "That email was distributed to another employee and that employee interpreted it as being real. At that point, that employee called 911 basically reading what the email said, which was an active shooter was inside the building."
We spoke with approximately a dozen people who were inside at the time of the drill and they told us the building management notified the offices of "a dangerous incident and to shelter-in-place."
Some workers told us they were very frightened by what was going on and made sure that their doors were locked and they stayed away from windows.
Police said they did not know anything about a drill and said that any time an office has a drill such as this needs to contact the police and let them know. In this situation, a large police presence descended to the building in response to the active shooter report.
Wakefield High School and Claremont Immersion school in Arlington County were briefly locked down as a result of the incident.
FOX 5 spoke to law enforcement officer about what went wrong and tips for a successful drill.
"Signage on every entry door, at every point, you want it to be very clear -- active shooter training in progress," said Scott Zimmerman, a full-time law enforcement officer and CEO of K17 Security.
His company conducts such trainings on a regular basis.
"Sometimes our active assailant has a knife, sometimes they have a gun," Zimmerman said as he showed us some of the tools used in K17 Security's active shooter trainings. "We want something that is very clear that if law enforcement responds or anybody else that sees it -- hey, it's a blue gun -- that does not look real."
Other tenants in the building on Leesburg Pike in the Bailey's Crossroads area were not aware of the drill. Neither were Fairfax County police, Arlington County Police or the FBI.
"There's no actual law in place that says if you do it, this is your steps you have to go through, you have to notify local law enforcement or anybody on the federal side," said Zimmerman. "It's sort of best practices."
He also explained the logistics for such trainings are complex and can even be risky. That is why it is important a trained professional conducts them. But he added that in his opinion, these trainings are essential and save lives.
"It's not a fun topic in any way shape or form," he said. "If somebody's here and they're trying to create carnage and trying to do bad things, it's something we need to train for now."