A 22-year-old college student has allegedly confessed to gunning down six people on the University of North Carolina-Charlotte campus Tuesday evening, killing two and wounding four.

Trystan Terrell now faces two counts of murder, four counts of attempted murder, four counts of assault with a deadly weapon with intent to kill, possession of firearm on educational property, and discharging firearm on educational property. A motive in the shooting remains unclear.

Sources tell sister station WBTV that Terrell had withdrawn from all but one class for the spring semester, and that it was the one remaining class -- Anthropology -- that he allegedly targeted late Tuesday afternoon.

Witnesses said the class was in the middle of presentations when "someone started shooting up the room."

Officers were already on campus for a Waka Flocka concert scheduled Tuesday night and were able to get to the scene within minutes. The gunman was still in the classroom and was quickly disarmed and taken into custody. Police have not commented further on what transpired when officers and suspect met.

Media at the scene said the alleged shooter grinned at cameras as he was escorted out in handcuffs.

Officers then went room to room to find students and faculty sheltering in place.

Late Wednesday morning, law enforcement identified the two killed in the shooting as 21-year-old Riley C. Howell and 19-year-old Ellis Parlier. Both are of North Carolina.

The surviving victims were identified as 20-year-old Rami Alramadhan, 23-year-old Emily Houpt, 20-year-old Sean Dehart and 19-year-old Drew Pescaro. Alramadhan is from Saudi Arabia; the others are from North Carolina.

Pescaro writes for the campus newspaper and was identified in a tweet by the paper Tuesday night:

A police briefing following the shooting can be viewed below: