Mystery surrounds three loud 'explosion-type' noises that woke many people up in a large part of Milton Keynes during the night.
People have reported hearing the noises at around 4am.
"I was in a deep sleep and they were loud enough to wake me... They sound like something exploding," said one man who lives on Peartree Bridge.
Other people in Bletchley also heard the bangs.
"It sounded like really loud gunshots," said one resident, while another agreed the noise sounded like explosions.
Many people in the Bletchley area had already been awakened at 1.45am by the sound of MK Stadium's siren-type alarm going off. This is not thought to be connected to the bangs.
Meanwhile police have taped off part of Drayton Road and Grassmere Way in Bletchley and there is still a police presence on the Lakes Estate.
It is understood a serious incident occurred last night, somewhere near Sycamore Hall.
The Citizen has asked police for details and we are awaiting a reply.