“Your brother never seemed like the kind of young man who would just disappear without a mighty important reason,” Gus Kramer agreed.

His tone was sincere, but I did not miss the glance he shot at his wife or the fact that she was nervously biting her lips.

“Did you ever consider the possibility that your brother may have experienced a cerebral hemorrhage or any other physical condition that might have given him an attack of amnesia or even partial amnesia?” Howard Altman asked.

“I’m considering everything,” I told him. I reached into my shoulder bag and took out a notebook and pen. “Mr. and Mrs. Kramer, I know it’s been ten years but could I just ask you to tell me what you remember about anything Mack did or said that might have some significance? I mean, sometimes we think of something that didn’t occur to us at the time. Maybe as Mr. Altman just suggested, Mack had some kind of amnesia attack. Did he seem in any way troubled or worried, or as though he wasn’t feeling well physically?”

As I asked these questions, I thought of how, after the police gave up on trying to find Mack, my father then hired private investigator Lucas Reeves to continue the search. For the last few days I’ve been reviewing every word of his files. Everything the Kramers told him was in my notes.

I listened as Mrs. Kramer hesitantly, then enthusiastically, told me how Mack was the kind of young man who always held the door open for her, who put his laundry in his hamper, who always picked up after himself. “I never saw him look troubled,” she said. The last time she had seen him was when she tidied up the apartment he shared with two other seniors. “Both of the other boys were out. He was working on his computer in his bedroom and told me the vacuum wouldn’t bother him. That’s the way he always was. Easy. Nice. Polite.”

“What time was that?” I asked her.

She pursed her lips. “About ten o’clock in the morning, I would guess.”

“That would be right,” Gus Kramer confirmed quickly.

“And you never saw him again?”

“I saw him leave the building at about three o’clock. I was on my way home from the dentist. I was putting my key in the lock of our apartment. Gus heard me and opened the door. We both saw Mack come down the stairs. He waved as he went through the lobby.”

I watched her glance at her husband for approval.

“What was Mack wearing, Mrs. Kramer?”

“What he had on in the morning. A T-shirt and jeans and sneakers and…”

“Lil, you’re mixed up again. Mack was wearing a jacket and slacks and an open-necked sport shirt when he left,” Gus Kramer interrupted sharply.

“That’s what I meant,” she said hurriedly. “It’s just I keep seeing him in the T-shirt and jeans because that’s when I had a little talk with him that morning.” Her face convulsed. “Gus and I had nothing to do with his disappearance,” she cried. “Why are you torturing us?”

As I stared at her I thought of what Lucas Reeves, the private investigator, had written in his file, that the Kramers were nervous that they might lose their jobs because of Mack’s disappearance. Now, nearly ten years later, I didn’t accept that reasoning.

They were nervous because they had something to hide. Now they were trying to keep their stories straight. Ten years ago Mrs. Kramer had told Reeves that Mack was just coming out of the building when she saw him and that her husband was in the lobby.

At that moment I would have bet my life that neither one of them ever saw Mack leave this building. Or did he ever leave it? That question rushed into my mind and was immediately dismissed.

“I know how long it’s been,” I said. “But would it be possible to see the apartment where my brother lived?”

I could see that my request startled them. This time both Kramers looked to Howard Altman for guidance.

“Of course, the apartment has been rented,” he said, “but since it’s the end of the term many of the students have already left. What is the situation in 4D, Lil?”

“The two who shared the larger bedroom are gone. Walter Cannon has Mack’s old room but he’s leaving today.”

“Then perhaps you could phone and ask if Ms. MacKenzie might stop in?” Altman suggested.

A moment later we were climbing the stairs to the fourth floor. “The students don’t mind stairs,” Altman told me. “I must say I’m glad I don’t go up and down them every day.”

Walter Cannon was a six-foot-four twenty-two-year-old who waved aside my apologies for the interruption. “I’m just glad you weren’t here an hour ago,” he said. “I had stuff all over the place.” He explained that he was on his way home to New Hampshire for a summer vacation and was starting law school in the fall.

He’s at the same point in time Mack was when he disappeared, I thought sadly.

The apartment coincided with my vague memory of it. A small foyer now stacked with the luggage Cannon would be carrying, a kitchen directly opposite the outer door, a hall to the right with a sitting room and bedroom off it, a bathroom at the end. To the left of the foyer, a second bath and, beyond it, the bedroom where Mack had lived. Not listening to Altman’s comments about how well the apartments were maintained, I walked into what had been Mack’s bedroom.

The walls and ceilings were off-white. A light flowered cotton spread was tossed on the bed. Matching drapery panels framed the two windows. A dresser, desk, and easy chair completed the furnishings. A wall-to-wall blue-gray carpet covered the floor.

“This apartment, like all the others after they’ve been vacated, will have a fresh coat of paint immediately,” Altman was saying. “The carpet and spread and drapes will be cleaned. Gus Kramer will make sure the kitchen and baths are spotless. We’re very proud of our units.”

Mack lived here for two years, I thought. I imagined him feeling about it the way I feel about my apartment. It was his own space. He could get up early or late, read or not read, answer the phone or not answer the phone. The closet door was open, and of course it was empty now.

I thought about the Kramers’ claim that he was wearing a jacket and open-necked shirt and slacks when he left that afternoon.

What was the weather like that day? I wondered. Was it one of those chilly May afternoons like last Sunday? Or, if it was very warm, and Mack did leave at three o’clock, would wearing a jacket have any significance? A date? A drive to a girl’s house in Connecticut, or Long Island?

It’s funny but in that room, ten years later, I had a sense of his presence. He was always so laid back. Dad had been competitive, quick to size up a situation, and, with lightning accuracy, appraise and judge it. I know I’m like that, too. Mack was more like Mom. He was always giving everyone a break. Like her, if he ever realized he was being used or treated shabbily, he wouldn’t have a confrontation, he’d simply withdraw from the situation. And that, I think, is what Mom is doing now-she views Mack’s note in the collection basket as a slap in the face.

I moved to the window, trying to see what he had seen. Knowing how Mack loved to stand at the windows of the Sutton Place apartment and study the panorama, the East River with boats and barges, the lights of the bridges, the air traffic heading in and out of LaGuardia Airport, I was sure he’d often gazed out these windows, overlooking West End Avenue, the sidewalks constantly streaming with people, the vehicle traffic bumper to bumper in the street.

The dream I had had of him after his predawn phone call on Mother’s Day replayed itself in my mind. Once again I was walking along a dark path, desperate to find Mack.

And once again he was warning me to stay back.