BARRIE, ONT. -- A single Barrie police cruiser remains in front of a home on Dunsmore Lane Wednesday, one day after a massive OPP investigation at the residence in the city's north-east end.

As many as 20 marked and unmarked police vehicles lined the street Tuesday, while police remained tight-lipped about the investigation.

Residents recall hearing a loud bang around 5 a.m. followed by officers on a megaphone demanding people inside the Dunsmore Lane residence come outside.

"I woke up to the big loud banging, actually yelling first they were yelling at whoever lives inside to come out. They did not come out," a neighbour recalled.

Meanwhile, police ordered everyone in neighbouring homes to remain indoors.

CTV News learned the investigation stretches to locations across Southwestern Ontario, including London, Brantford, Ancaster and Brant County.

In a statement to CTV News Tuesday, provincial police said, "We want to assure residents in all affected locations that appropriate safety measures have been taken. There is no threat to public safety."

The OPP said it would provide more information on the investigation in the coming days.