The Boston Bruins held a moment of silence Tuesday night to honor the lives lost over the weekend in two shootings, one at Brown University in Rhode Island and one at Bondi Beach.

After determining that a man they had detained was not the killer, Rhode Island officials have searched for more evidence and released photos of a possible gunman.

The ongoing effort to find a man who walked onto Brown University ’s campus during a busy exam season and shot nearly a dozen students in a crowded lecture hall has raised questions about the school's security systems and the urgency of the investigation itself.