I STARED INTO Mrs. Vetter’s ice-blue eyes until she broke the spell. She turned her head to the side and cried out, “Hans, do what they tell you!” As she turned her head, the yellow shawl dropped away. My heart bucked as I realized that there were two people sitting in that wheelchair.

  Mrs. Vetter was sitting in her son’s lap.

  “Hans, do what they tell you,” Vetter mimicked.

  The chair rolled forward onto the lawn. I saw clearly now. Vetter’s huge right hand was on the chair’s power controls. His left arm crossed his mother’s body, and he held the muzzle of a sawed-off, double-barreled, twelve-gauge shotgun hard against the soft underside of his mother’s jaw.

  I lowered my Glock 9 and forced a level of calm into my voice that I didn’t remotely feel.

  “Hans, I’m Sergeant Boxer, SFPD. We don’t want anyone to get hurt. So just throw that gun down, okay? There’s a safe way out of this situation, and I want to get there. I won’t shoot if you put down that gun.”

  “Yeah, right,” Vetter said, laughing. “Now listen to me, both of you,” he said, pointing his chin at me and then at Co............