Later in the theater’s greenroom, Pitta and Robin were mingling with another comedian who had brought his service dog. As Pitta recounted the scene, “I just casually said, ‘Another comedian I know has a service dog. The dog wakes her up when she chokes in her sleep.’ And Robin instantly said, ‘Oh, a Heimlich retriever.’ It got a huge laugh. He just sat there and had a little smile on his face.” When he and Robin left the theater at the end of the evening, Pitta said, “I gave him a hug and I said goodbye. He said goodbye to me three times that night. And he said it exactly the same way. He goes, ‘Take care, Marky.’ He said it three times.”

One evening in early August, Robin made one of his intermittent visits to Zak and Alex’s house in San Francisco, as he did when Susan was out of town. This time she happened to be in Lake Tahoe, and Robin showed up to see his son and daughter-in-law like a meek teenager who realizes he’s stayed out past his curfew; he was always welcome there, but he carried himself with mild discomfort, as if he still needed someone else’s permission to be in their home. At the end of the night, as Robin was preparing to head back to Tiburon, Zak and Alex asked him what it would take to keep him at their house—would they have to tie him up and throw a bag over him?

“Well, that was a joke,” Zak said with a bittersweet laugh. “To be clear, that was a joke. But we didn’t want someone who seemed like he was in so much anguish to leave. We wanted him to stay with us. We wanted to take care of him.”

On the night of August 10, a Sunday, Robin and Susan were home together in Tiburon when Robin began to fixate on some of the designer wristwatches that he owned and grew fearful that they were in danger of being stolen. He took several of them and stuffed them in a sock, and, at around 7 P.M., he drove over to Rebecca and Dan Spencer’s house in Corte Madera, about two and a half miles away, to give them the watches for safekeeping. After Robin came home, Susan started getting ready for bed; he affectionately offered her a foot massage, but on this night, she said she was O.K. and thanked him anyway. “As we always did, we said to each other, ‘Good night, my love,’ ” Susan recalled.

Robin went in and out of their bedroom several times, rummaged through its closet, and eventually left with an iPad to do some reading, which Susan interpreted as a good sign; it had been months since she’d seen him read or even watch TV. “He seemed like he was doing better, like he was on the path of something,” she later said. “I’m thinking, ‘O.K., stuff is working. The medication, he’s getting sleep.’” She saw him leave the room at around 10:30 P.M. and head to the separate bedroom he slept in, which was down a long hallway on the opposite side of their house.

When Susan woke up the next morning, Monday, August 11, she noticed that the door to Robin’s bedroom was still closed, but she felt relieved that he was finally getting some needed rest. Rebecca and Dan came over to the house, and Rebecca asked how the weekend had gone with Robin; Susan optimistically answered, “I think he’s getting better.” Susan had been planning to wait for Robin to wake up so that she could meditate with him, but when he wasn’t awake by 10:30 A.M., she left the house to run some errands.

By 11 A.M., Rebecca and Dan were concerned that Robin still had not come out of his room. Rebecca slipped a note under the door of Robin’s bedroom to ask if he was O.K. but received no response. At 11:42 A.M., Rebecca texted Susan to say she was going to wake Robin up, and Dan went to find a step stool to try to look through his bedroom window from the outside of the house. In the meantime, Rebecca used a paper clip to force open the lock to the bedroom door. She entered the room and made a horrifying discovery: Robin had hanged himself with a belt and was dead.

Excerpted from Robin by Dave Itzkoff. Published by arrangement with Henry Holt and Company, May 15, 2018. Copyright © 2018 by Dave Itzkoff. All rights reserved.