Authorities say an Alabama biology professor accused of fatally shooting three colleagues at a faculty meeting had been denied tenure, which provides job security.

University spokesman Ray Garner said Saturday that the professor, Amy Bishop, had been informed months ago that she would not be granted tenure. He said the faculty meeting where she is accused of gunning down colleagues was not called to discuss tenure.

At a news conference Saturday, authorities declined to comment on a possible motive. But family members of victims say they understood that the shooting involved Bishop's tenure.

Prosecutors charged Bishop with capital murder, which can bring the death penalty if convicted. District Attorney Ron Broussard said he did not think Bishop has a lawyer.