Driving back to my office, I was convinced Nick was implicated in Bill’s death but I no longer suspected he had killed him. From Nick’s description of their relationship it was clear that Nick was Bill’s hostage, emotionally manipulated to remain with him. In that state, even if Nick had reached a breaking point and decided his only way out was to kill Bill, he would have lashed out at him impulsively in a sudden fury. He would not have concocted an elaborate and premeditated plan involving carbon monoxide poisoning.

I considered another scenario. Maybe the gas leak was accidental and when Nick woke up and smelled the gas, Bill was unconscious in the bed beside him. Nick panicked and called his brother. Sal told him to get out of the apartment. Instead, Nick returned to the bedroom and saw Bill was still breathing. In that moment, he had a choice: try again to rouse Bill and drag him out of the apartment or leave him there. By now, Nick would have been disoriented, struggling to breathe and unable to think clearly. In that confused state, he left Bill behind. It would be easy for Nick to now blame himself for Bill’s death because it had liberated him from Bill. But had he killed him? Under the circumstances, he might have died himself had he tried to rescue Bill. Whatever had been in his mind in those moments, the law would not have held him responsible for Bill Ryan’s death. Which is not to say he wouldn’t still feel guilty. He might even believe he did have some criminal as well as moral liability. That would explain why he refused to talk to me about what had happened that night.

Where did this leave me? I still had a report to write. I needed someone in that family to answer my questions.

Isabel Trejo’s office was in an old building on Montgomery Street that featured a grand marble lobby at street level and sepulchrally austere corridors on the upper floors. Her name was written in gilt on the frosted windowpane of an oak door. I entered a small anteroom furnished in the usual heavy, dark, lawyer office furniture. Behind sliding glass windows, a middle-aged woman glanced up at me, slid back the glass and said, “Can I help you?”

“I have an appointment with Ms. Trejo. I’m Henry Rios.”

She glanced down at a sheet of paper. “I’ll let her know you’re here.”

I sat down and thumbed through a two-month old issue of the ABA Journal. After a couple of minutes, the door to the inner office opened and a tall, dark-eyed woman in the standard navy-blue suit favored by women lawyers strode into the anteroom. “Mr. Rios?”

I stood up. “Ms. Trejo?”

She looked me up and down, frowned briefly as if she’d come to a not entirely favorable conclusion, and said, “Come in.”