Police have interviewed students at the magnet high school, although Wilson said, "Right now we have a lot of unanswered questions".
The shooting occurred in a classroom at Huffman High School in east Birmingham during the school's afternoon dismissal.
Birmingham City Schools also released a statement regarding the shooting.
Killed was a 17-year-old girl who was going to graduate in May, had already been accepted into college and had dreams to become a nurse.
"Our hearts are heavy", he said.
Reports earlier said a 17-year-old girl died on the way to hospital and two people were injured in the shooting, including a 17-year-old boy, who was in critical but stable condition, and an adult employee who was treated and released at the scene. Later on, he was interrogated by officials at the police headquarters.
Police had begun piecing together the events that lead to the student's death around 3:45 p.m. Wednesday.
Authorities recovered the gun used, but it was not immediately clear who fired the weapon and no arrests were immediately made. Another 17-year-old was shot. "We'll give you the answers as they come, even though I'm happy to share what I know". She was given CPR at the scene of the "accident" and on the way to the hospital, but was never revived.
Police said there was surveillance video they will be reviewing and possibly some witnesses, but as of Wednesday evening, details surrounding the shooting were scarce.
Sources said a male student was "showing off" his gun when it discharged, striking the female student.
"We're not saying he shot her, we're not saying he didn't shoot her", Wilson said. "We're asking those questions ourselves so we can determine exactly what happened". Just last week, as police and school officials investigated a reported threat at Huffman Middle School, a gun was found outside an entrance door, believed to have been left there as students prepared to be scanned and have their backpacks checked.