Police say Thursday they're acting on a request by Quebec's director of criminal and penal prosecutions. Police add that after evidence is collected it will be determined if there are grounds for prosecution.
The NHL said a day earlier it would not suspend Chara for Tuesday night's hit, when he slammed Pacioretty into a glass partition.
There has been strong debate this season over injuries from hits to the head. Pittsburgh star Sidney Crosby is among those sidelined with such an injury.