A high school student thought they heard the sound of a shotgun racked while inside a bathroom and called 911.

The dispatcher erroneously passed it on as an active shooter call.

That led to a multiagency police response just before 10 a.m. to Lake Central High School on Wednesday, officials said at an afternoon press conference at the St. John Police Station. The school cop quickly determined no gun was found and no one was hurt, St John Police Chief Steven Flores said.

The officer located two students — one who thought he heard the noise and his friend — and brought them to the main office for questioning.

They were later released.

A third student was in the bathroom at the time, but had no idea what was going on, Flores said.

Parents were told to wait by the Fagan-Miller Funeral Home parking lot - a pre-selected staging area - for more information. They were told students were safe, he said.

Because of the dispatch report, police — from East Chicago to Cedar Lake, and federal agencies including the ATF and FBI — went to the school thinking there might be an ongoing shooting.

“That’s a conversation that we probably need to address and speak with the dispatch center about,” Flores said. “I’m a parent, too, and if my kid was in that school, I’d be worried. Who knows what kind of information was being shared out there.

“That’s why we were trying to stay ahead of the game..before people were putting rumors out there,” he said.

Lake Central is one of Northwest Indiana’s biggest high schools with nearly 3,300 kids. Superintendent Larry Veracco said he was grateful for the fast police response.

Officers searched the school “room to room”, the students’ cars, and surrounding area, Flores said. Part of Indianapolis Boulevard was blocked off for security and the search for a possible weapon.

Police are still in the process of gathering information and welcome any tips from students, he said. Earlier that day, a robocall released by Veracco said that at approximately 9:30 a.m., the high school was put on lockdown after someone made a 911 call. No shots were fired, and no one was injured.

Roger Patz, public information officer with the St. John Police Department, said that U.S. 41 between 77th and 85th Streets would be closed for the better part of the afternoon so that law enforcement could conduct a “slow, methodical search” of the entire school campus and surrounding area. They were conducting the search because police “don’t know for sure that there is gun,” he said.

Patz also couldn’t confirm that there are two students in custody. Patz praised law enforcement’s “tremendous” response to the call.

Also, on Twitter, the Schererville Dairy Queen has announced that it would remain closed Wednesday. “We think it’s important for team members to be with their families,” a tweet said.