Employees at a Pomona supermarket were allowed to return to work after a heavy police presence was seen outside of the store early Wednesday.

Officers were seen outside of the Winco Foods where, at around 5:15 a.m., about a dozen officers were seen walking into the store with their guns drawn.

A police robotic dog followed shortly after with another set of officers. 

It was not immediately clear what prompted the police presence at the supermarket, which is open 24 hours a day.

Winco Foods shut down as the investigation continued, but at around 6:30 a.m., employees were allowed to return to the store and police left the scene.

No further details were immediately available.