CHAPEL HILL, N.C. (WTVD) -- Three federal search warrants were unsealed in the case of the UNC graduate student accused of shooting and killing his professor.
That deadly shooting happened on campus inside a school building while class was in session.
Tailei Qi is the student accused of the shooting. The warrants revealed that Qi and his professor Dr. Zijie Yan were overheard arguing before five gunshots rang out inside Caudill Laboratories.
The warrants also show that Qi visited a gun range in the days leading up to the Aug. 28 shooting.
After the shooting, police searched Qi's apartment and found a notebook with login information for two different firearm website forums. On those forums, users sell and discuss guns.
The documents help shed light on how authorities zeroed in on Qi.
His arrest was made off-campus less than two hours after the initial call of shots fired, about two miles from Caudill Labs.
We now know that witnesses were able to immediately identify Qi as the shooting suspect.
There are also new details about the weapon allegedly used in the crime.
That's been one of the key questions of this case as Qi, a foreign national, faced substantial limitations in legally owning a weapon.
These newly unsealed warrants state that multiple witnesses at the scene told officers they knew the shooter and provided a clothing description that matched Qi's apparel.
One witness, who was in an adjacent office, heard an argument between Qi and the victim - and then five gunshots.
That witness then saw Qi walk by holding a gun in his hand.
As authorities rushed to campus, Chapel Hill Police received a 9-1-1 call about a man matching Qi's description running in the woods about a mile away from his apartment.
It appears authorities believed that between the shooting and his eventual arrest, Qi was "likely attempting to avoid detection from law enforcement and possibly attempting to destroy or hide evidence."
Triangle criminal defense lawyer Ralph Frasier Jr. helped explain the process behind the release of this information.
"Because they are doing an investigative portion of it, then they typically will seal oftentimes warrants that that information isn't leaked out and somehow destroys the integrity of that investigation itself," Frasier said.
Qi's vehicle was found in a parking lot near the crime scene, and the unsealed documents say he admitted being in the lab that morning but said he fled campus after receiving the alert of the shooting and further denying that he had any altercation with Yan, whose research team he had been part of.
Qi was arrested without incident - and without a weapon in his possession.
Qi was committed to Central Regional Hospital in Butner for psychological treatment after a judge determined he was unfit for trial.
The judge said two separate mental evaluations found Qi likely suffers from untreated schizophrenia. Because of that, the judge said, Qi cannot comprehend his situation, assist in his legal defense, or even understand court proceedings.