Ahmad Rahami, the suspect in the bombings, was a gregarious, friendly man who was obsessed with fast cars and seemed to be in the process of taking over the daily operation of his family’s fast-food restaurant on Elmora Avenue in Elizabeth, a gritty commercial street, a restaurant patron said.

“When it first opened it was the father 24 hours a day,” the patron, Ryan McCann, said. Gradually, Ahmad replaced his father behind the counter, Mr. McCann, 33, said.

Other neighbors said they believed the elder Mr. Rahami had four sons, and perhaps two daughters, plus a wife. They lived in the apartments upstairs from the restaurant, First American Fried Chicken.

For years, Ahmad was a friendly face, Mr. McCann said. He wore Western clothes, hung out on the sidewalk with friends, and often slipped his regular customers free food.

“He’s a very friendly guy, he gave me free chicken,” Mr. McCann said. “He was always the most friendly man you ever met.”

Mr. McCann said that Mr. Rahami had a passion for Honda Civics custom-built to race.

“He always talked about fast Honda civics, about how he loved them,” Mr. McCann said.

On Monday morning, the authorities hauled away a white Infiniti five-seater and were inspecting a blue BMW sedan and a black Toyota Camry near the Rahami home.

Mr. McCann said he last ate at the restaurant two weeks ago. Ahmad served him, and was in usual form.

“He was having a conversation about his cars,” Mr. McCann said. “How he likes to soup ’em up and race ’em.”

He was deeply rattled by this morning’s news.

“He’s a guy you would never expect,” he said. “This is sad, terrifying, scary.”