A representative for Valparaiso Community Schools also confirmed Flint Lake Elementary School, Thomas Jefferson Elementary School and Thomas Jefferson Middle School were on a modified lockdown in response to the situation.

There were 10 people in the office at the time the incident began, Grennes said, and just before 11:30 a.m., two men and two women were seen leaving the building, none appearing injured. About 12:40 p.m., another woman was seen walking out of the building unharmed.

One of the hostages was taken to Porter hospital, Grennes said, after being struck in the head by Ferguson. Police said it was unknown whether Ferguson struck the person with his hand or his weapon. The injured person was treated and released, Grennes said.

About 1:30 p.m., armed SWAT team members were seen entering the neighboring Urschel Laboratories building and others climbing onto the roof of the Midas auto shop next door.

The final hostages were released shortly after 3:30 p.m., though Ferguson stayed holed up in the building and in communication with FBI negotiators.

At 4:43 p.m., two loud bangs were heard echoing down Calumet Avenue, as an armored SWAT vehicle pulled up to the building and an officer entered through a shattered first-floor window.