Brown University Shooting Initially Thought to Be 'Mass Casualty' Event, Dispatch Audio Reveals

Providence, Rhode Island officials thought there could be upwards of 20 victims in the Brown University shooting ... according to dispatch audio.

After the initial call for the shooting came in, first responders showed up at the campus swiftly ... and, they relayed increasingly troubling estimates on the number of potential victims.

Listen to the clip for yourself ... early on, someone says they believe there are 6 victims in the shooting -- before someone later revises by saying there could be as many as 20 victims.

One person on the line then then says, "It's officially going to be a mass casualty event ... If there's possibly 20 victims, we're going to need as much mutual aid as you can get."

Individual victims are also described in the audio ... one was shot in the back according to dispatchers -- while another is lying injured in a stairwell.

As we told you ... Providence Mayor Brett Smiley announced two people are dead, while 8 others have been rushed to the hospital in critical condition. Mayor Smiley did say the death and injury toll could rise.

Brown University was put on lockdown this afternoon when shots were initially fired at the Barus & Holley building on the eastern side of campus ... with school officials telling students to shelter in place.

Later on, Brown announced a suspect was in custody, but urged people to continue to shelter ... which is fortunate since it turns out police hadn't caught the alleged shooter. Police later explained they engaged in a confrontation with someone who was not actually connected to the shooting which led to the confusion.

Officers have not yet recovered the firearm used in the shooting ... and, they only know the shooter is a male dressed in all black.