"Originally, when we were coming down here, we believed that there could be possibly hostages involved and a shooting going on inside," Sgt. James Lesnansky, Aurora Police, said.
The situation started around 10:15 a.m. at a Wells Fargo at 999 S. Sable Blvd., which is near E. Mississippi Avenue.
Debra Brassell had just left the bank when police started to arrive.
"They had guns drawn. Everything was blocked off," said Brassell. "And, then all of a sudden, I get a phone call saying that my bank was being robbed."
Police say workers from an armored car company were servicing and ATM when one of its security guards heard the pops. Police say he was locked inside a secure ATM room, and called 911, reporting it as a possible bank robbery in progress with shots fired.
A spokesman for Wells Fargo says a few helium balloons, decorating the bank lobby for New Year's, floated to the ceiling and popped.
Police responded to the situation as though it were a real bank robbery with shots fired, asking people to stay out of the immediate area, near the intersection of E. Tennessee Drive and S. Sable Boulevard, just north of E. Mississippi Avenue, and calling the FBI.
More than a dozen officers set up a perimeter, but that was later called off shortly after 11 a.m.
Despite the fact that it turned out to merely be popping balloons, police say the guard took the correct action.
"If he would've opened the door and there were actual robbers out there, you don't know what's going to happen once they go inside," said Sgt. Lesnansky. "So, he did the proper thing staying in a secure area and giving us a call."
Brinks Denver released this statement about its security officer, "He followed protocol 100 percent and responded properly to the circumstances."
Police closed Sable Boulevard in both directions from Mississippi to Kentucky during the incident.
Wells Fargo released the following statement after the incident:
"The safety and welfare of our team members and customers is a top priority. We thank the Aurora police department for their quick response and are grateful this unfortunate incident was quickly resolved."
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