Might have Shipton faked the accident in some sick attempt to place the blame on David Dean whom he obviously despised? By all accounts his injuries were far too severe to have been logically self-inflicted.
Somehow, considering Gladys, Effie or Claire seemed to stretch common sense more than an overweight bungee jumper. Dean couldn't bring himself to think of any of them seriously, given their lack of reasonable motive. Unless one of these people had a reason to kill Shipton beyond the apparent. Janet? Even more of a stretch, in Dean's mind. He considered Donald Ryland. Perhaps in cahoots with Edith? Not if outward appearances meant anything. Ryland gave no indication of having any interest in furthering his relationship with the mother of his out-of-wedlock son.
The remaining possible suspects were young Donnie and Cynthia. Dean was reluctant to even consider either option. He wanted desperately to dismiss Cynthia from consideration. Regardless of what she had said, he couldn't conceive of her killing someone with the possible exception of self-defense or protection of another. Shipton's fall did not fit either category. While she despised the man, her feelings still lacked a motive to sever his rope in cold blood and watch him plummet down to the rocks and churning river below. And yet, Cynthia was disturbed about something moments after the incident.
Suddenly, he had a thought. Might have his wife witnessed the attempted murder? That made some degree of sense. But why not immediately tell someone? Logic began to drift back into Dean's thought process. The obvious answer was to protect that person. But whom? Her husband? No. Dean hadn't been in the vicinity of Shipton's fall. There was no reason for her to even think he might be involved. Fred? Again, no. Fred's life was a mystery in some respects but he was honest and his report of Cynthia after Shipton's fall was certainly not a fabrication. There was no reason for Cynthia to protect any of the other adults. That left Donnie Ryland. The young boy would be the only person Dean could think of who Cynthia would care enough to at least consider protecting.
While he hated even speculating about a child murderer, it was the first time Shipton's attempted killing began to make any sense. There was one way to settle the matter. As Dean drew close to Bird Song, he resolved to ask his wife point blank if she witnessed Donnie Ryland cutting his stepfather's climbing rope in an attempt to send him to his death.
A small red sports car skidded to a stop in front of Bird Song as Dean dismounted his bike. A tiny red haired woman, under five feet, Dean guessed, emerged from the vehicle that bore Colorado license plates. She stamped out her cigarette in the snow before pulling a large suitcase from the small rear seat, nearly yanking off the handle and serenading the action with a chorus of curses. Dean moved to assist her after setting his bike against the porch.