ONE Dr. David Mitchell waved me toward the dead professor's chair. "Try it out, son." Mitchell and Detective DeLeon sat down on the students' side of the desk, the safe side. I took the professor's chair. It was padded in cushy black leather and smelled faintly of sports cologne. Walnut armrests. Great back support. Mitchell smiled. "Comfortable?" "I'd be more so," I told him, "if the last two people who sat here hadn't died." Mitchell's smile thinned. He glanced at Detective DeLeon, got no help there, then looked wearily around the office — the cluttered bookshelves, file cabinets topped with dreadlocks of dying pothos plants, the tattered Bayeux tapestry posters on the walls. "Son, Dr. Haimer's death was a heart attack." "After receiving death threats and being driven out of the job," I recalled. "And Haimer's successor?" Detective DeLeon sat forward. "That was a .45, Mr. Navarre." When DeLeon moved, her blazer and skirt and silk blouse shimmered in frosty shades of gray, all sharp creases and angles. Her hair was cut in the same severe pattern, only black. Her eyes glittered. The whole effect reminded me of one of those sleek, fashionable Sub-Zero freezer units, petite size. She tugged an incident report out of the folder in her lap, passed me a color Polaroid of Dr. Aaron