The shooter was caught outside the Shelby Center, a science building, without incident, according to university spokesman Ray Garner. He said he could not identify her or the victims. Local media reported the shooter was a faculty member.
No students were involved, Garner said. All three of those killed and two of the injured were faculty members. The third injured person was a staff member.
Huntsville Hospital spokesman Burr Ingram said two of the injured were in critical condition and the third was in stable condition.
Sophomore Erin Johnson told The Huntsville Times a biology faculty meeting was under way when she heard screams coming from the room.
University police secured the building and students were cleared from it.
The Huntsville campus has about 7,500 students in northern Alabama, not far from the Tennessee line. The city is home to NASA's Marshall Space Flight Center.
The university posted a message on its Web site Friday afternoon telling students the campus was closed Friday night and all students were encouraged to go home. Counselors were available to speak with students.
Garner said at a news conference that the shooting was not unlike one the area experienced a week ago, when a 14-year-old student was killed in a middle school hallway, allegedly by a fellow student.
"This town is unaccustomed to shootings and multiple deaths," he said.
