From USA TODAY.

Authorities on Monday resumed their search for the gunman in the deadly attack at Brown University that killed two students and wounded nine others after investigators released a person of interest.

At a news conference late Sunday, Providence, Rhode Island, Mayor Brett Smiley and other Rhode Island officials told reporters the previously detained man could not be charged and that the investigation was going in "another direction."

Smiley said there will be an enhanced police presence on the Ivy League campus and throughout the city as local, state and federal investigators work to identify and locate the gunman who burst into a classroom in an engineering building and opened fire on Saturday.

"We have not yet solved this case, but I am confident we are going to do that in the near future," Rhode Island Attorney General Peter Neronha said