It seems it was an active shooter but some sources said it was a false report. At no point were any firearms discharged, Lt. Hank said. However witnesses recounted a chaotic scene. People began running for the doors, and some gamblers got trampled. The high-end resort was on lockdown for roughly half an hour. A preliminary investigation suggested that at least three robbers used a sledgehammer to break in, the police spokesman said. No one was injured. One witness posted to Twitter a picture of a person wearing what appeared to be a pig mask . Some people were detained, but it is unclear if the detained individuals are burglary suspects. The Bellagio is home to several high-end jewelry and watch stores, including Tiffany, Tesorini, Omega and Harry Winston.