He thought it was falling furniture.

The morning service was just beginning on the second floor of Tree of Life synagogue in Pittsburgh’s Squirrel Hill neighborhood on Saturday when E. Joseph Charny heard a loud noise from downstairs.

“It sounded like some big thing falling over, like a coat rack,” Charny said.

There were about six to eight congregants bowing their heads in the pews, along with Charny, all of them waiting solemnly for the weekly services to get started, people Charny knew well. A man appeared in the doorway. Charny doesn’t remember him saying anything. Gunshots cracked across the chamber.

“I looked up and there were all these dead bodies,” said Charny, 90, a retired psychiatrist from Squirrel Hill. “I wasn’t in the mood to stay there.”

So Charny ran away from the man, avoiding the bullets.

Law enforcement officials say the man who shot at the group was Robert Bowers, a 56-year-old area resident who allegedly was in the middle of the deadliest attack on Jews in the nation’s history. Authorities are investigating anti-Semitic statements Bowers allegedly posted online, including one shortly before the attack saying he was “going in.” The massacre targeted a building that houses three separate synagogues at the heart of Pittsburgh’s tightknit Jewish community.

By the time Pittsburgh police confronted the suspect, shooting and subduing him, 11 worshipers were dead.

Charny is a longtime member of the synagogue, attending services there since first moving to Pittsburgh with his family in 1955. His intimate knowledge of the building’s mazelike nooks and crannies probably saved his life. As bullets ripped through the room, Charny and two others – the rabbi and his assistant – fled for the building’s third floor.

“The building is complicated,” he explained. “It started off small but then has had a lot of additions. So there are a lot of small spaces. The three of us knew the small spaces.”

Charny found himself tucked into a storage room stuffed with cardboard boxes. The building was silent, he said. Anxious thoughts crashed inside his head: How long are we going to be here? Is he coming? How would they get out?

“We all knew leaving too soon would have been our deaths,” Charny said.

Pittsburgh police said they followed the shooter to the synagogue’s top level, where he allegedly had been stalking from room to room on the other end of the building from where Charny hid. Police said Bowers and responding officers exchanged gunfire – two officers were hit multiple times, and one was critically wounded. Bowers also was shot in the firefight. After he was taken into custody, he allegedly told a SWAT operator “that he wanted all Jews to die and also that they were committing genocide to his people.”

Charny and the two others with whom he was hiding eventually slipped out of their hiding places, emerging outside the synagogue, where they were met by police. Charny is recovering at home from his close call.

“At first I felt numb, then thankful,” he said. “I don’t need to tell you how terrible this has all been.”