Irving Police started receiving 911 calls at 11:33 a.m. CT. They arrived at the two-year community college before noon and found the victim in one building and the suspect in another, officials said.
The body of Janeera Nickol Gonzalez, 20, was found in a common study area in the school's Performance Hall Building, Irving Police Officer James McLellan said in a statement.
Adrian Victor Torres, 21, was found in a locker room shower stall in an adjoining building dead from what appeared to be a self-inflicted gunshot wound, McLellan said.
Investigators are working to determine the relationship between the two and whether they were students.
Student Joseph Le told CNN he was in a campus building when he heard three shots and a male yell, "Leave her be!"
Le, who said he then took cover, said the shots sounded like they were fired inside the building.
Another student, Haseeb Ahmed, was in class when he heard three gunshots, he said. It wasn't immediately clear where the shots were fired.
Ahmed and his classmates barricaded the door to their classroom, he said.
"We gathered the hardest materials in our possession to throw if something happens," he said.
As news of the gunfire spread, the college urged students and staff to lock themselves in rooms. After police said the suspect was dead, the school canceled the rest of the day's classes and closed campus Thursday and Friday.
North Lake College is a community college that had more than 11,000 students in fall 2013, the most recent semester for which the school posted data on its website.