Ms. Behar’s husband, Moises Behar, and the couple’s 15-year-old son, David, survived the crash.

Daniel, a sixth grader, and his brother, David, were inseparable, said Brett Meincke, 16, who has lived next door to the Behars for the past 12 years.

He said Ms. Behar was like a second mother to him. She frequently welcomed him to her house when he was spending time with her sons, and she would often invite him to tag along on family outings, he said.

The Behar family had traveled to Mexico to celebrate Mr. Behar’s birthday, he said.

A neighbor of Ms. Shamis, Richard Weinstein, 52, said he had known her since December 1999, when she and her husband, Arkady, moved into their gated neighborhood at the same time as he did.

The couple had immigrated to the United States from the former Soviet Union, Mr. Weinstein said. Over the years, they invited him to their home several times to eat. Ms. Shamis introduced him to some classic Eastern European recipes; in particular he recalled that she had made him borscht, a traditional vegetable soup.

But Mr. Shamis died in February, Mr. Weinstein said; he said he remembered seeing Ms. Shamis afterward, and she spoke of a desire to travel.