New Delhi, Dec. 20 -- A homeless man has been credited with breaking open the investigation into the deadly shootings at Brown University and the Massachusetts Institute of Technology (MIT), leading authorities to identify the suspected gunman and triggering a $50,000 reward payout.

The tipster, identified only as John, played a pivotal role after confronting the suspected shooter and later alerting police to critical details about his vehicle.

"He blew this case right open," Rhode Island Attorney General Peter Neronha said, praising the tipster's actions.

According to officials, John's information helped investigators identify Claudio Neves Valente, 48, as the suspect in the shootings that left two Brown University students dead and a...