A University of Arizona professor was shot and killed in an office on campus Wednesday, <\/b>university police said. A former student at the university has been charged.<\/p>\n<\/div>\n The shooting devastated those who knew Thomas Meixner, the head of the Hydrology and Atmospheric Sciences Department at the university, who was described by many as a kind and brilliant man. It frightened the campus community as students fled classrooms and tried to barricade themselves into rooms when the university sent alerts. And it reignited concerns nationally about some of the risks that can arise in academia.<\/p>\n<\/div>\n<\/div>\n Murad Dervish, 46, was taken into custody several hours after the shooting, University of Arizona Police Chief Paula Balafas said Wednesday.<\/p>\n<\/div>\n Dervish was charged Thursday with first-degree murder and aggravated assault with a deadly weapon, a campus police spokesman said. He said the motive is not yet known.<\/p>\n<\/div>\n The incident unfolded quickly. A man entered the John W. Harshbarger building about 2 p.m. Wednesday, according to the University of Arizona Police Department. Someone called police at 1:59 to say that a former student who was not allowed in the building had entered, and requested that police escort the man out.<\/p>\n<\/div>\n The department then received another call that there had been a shooting in the building. At 2:07 p.m., police were told the man had run out of the building\u2019s main entrance.<\/p>\n<\/div>\n Meixner was taken to the hospital, where he was pronounced dead.<\/p>\n<\/div>\n Dervish, 46, was taken into custody at 5:10 p.m. Wednesday at a traffic stop outside Gila Bend, Ariz., about 120 miles northwest of the university\u2019s campus.<\/p>\n<\/div>\n Sgt. Sean Shields, a spokesman for the university\u2019s police department, said Dervish had been expelled the previous semester.<\/p>\n<\/div>\n A campus exclusionary order<\/a> had been filled out to ban Dervish <\/b>but it had not yet been served because police could not locate him, Shields said Thursday. Shields said he was not sure whether the exclusionary order would have applied to the entire campus, a specific building or other area.<\/p>\n<\/div>\n An attorney for Dervish could not immediately be located.<\/p>\n<\/div>\n On Thursday, many mourned Meixner, a longtime presence on the Tucson campus.<\/p>\n<\/div>\n \u201cTom was always smiling \u2014 when I think of Tom, that\u2019s my first impression,\u201d said Xubin Zeng, a professor in the department of Hydrology and Atmospheric Sciences, who said Meixner had been a colleague and friend of 15 years. \u201cHe was always kind to everybody.\u201d<\/p>\n<\/div>\n Zeng said he had taught Dervish, and that members of the department are shocked, saddened and angry.<\/p>\n<\/div>\n Purdue student arrested after allegedly stabbing roommate to death<\/a><\/span><\/p>\n<\/div>\n The broader scientific community shared memories and tributes to Meixner\u2019s research contributions but even more so to his personal contributions as a mentor, friend, role model and family man.<\/p>\n<\/div>\n Paul Brooks, a <\/b>professor of hydrology at the University of Utah, had been friends with him since graduate school. \u201cHe really was a gifted interdisciplinary scientist who could connect chemistry, hydrology and biology together for really meaningful, insightful work,\u201d Brooks said.<\/p>\n<\/div>\n \u201cBut the most important thing about Tom is he was such a powerful force for good in science and academia in a very competitive world where things often aren\u2019t fair, and where people work very hard and maybe aren\u2019t acknowledged to the level they should be. He was incredibly unselfish and supportive of everyone.\u201d<\/p>\n<\/div>\n Rebecca Barnes, an <\/b>AAAS science technology policy fellow with the National Science Foundation, said she first met Meixner as a star-struck postdoctoral student. \u201cOne of the amazing things about being a scientist is knowing people in all these different stages of our lives,\u201d Barnes said. <\/b>\u201cBut it also means that our community, we feel these losses really hard.\u201d<\/p>\n<\/div>\n She said Meixner was warmly supportive of efforts to make science more equitable and inclusive, and remembered him enthusiastically \u2014 in all caps \u2014 promoting a colleague\u2019s work when Barnes was creating Wikipedia pages to highlight women in STEM fields.<\/p>\n<\/div>\n \u201cHe was one of those people who is both very smart and very nice, and that\u2019s who you want in science,\u201d she said. \u201cThat\u2019s who you want training the next generation.\u201d<\/p>\n<\/div>\n Meixner, who grew up in Maryland, graduated from the University of Maryland in 1992, according to his faculty homepage, and earned his doctorate in hydrology in 1999 from the University of Arizona.<\/p>\n<\/div>\n Christopher L. Castro, the associate department head, did not immediately respond to a request for comment but posted on social media about the loss, writing<\/a> that he was devastated. \u201cBeyond his professional contributions to hydrology, Tom was a father and an exemplary human being. Praying all who mourn, especially his family. I will miss you forever, my dear friend.\u201d<\/p>\n<\/div>\n