Const. Ian MacDonald says the officer was treated for exposure to fumes released when the bottle blew up outside a home on Thursday evening.
He says both explosions were in an area where a series of arsons occurred last month.
In the first incident on Tuesday, police and fire officials responded to reports of a loud noise and found remnants of a plastic two-litre pop bottle on the street.
MacDonald calls the incidents troubling, saying that besides the mischief involved, there's a potential for injuries and property damage.
Police are asking residents to report any suspicious activity.
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