Sarah Milgrim’s parents didn’t know that Yaron Lischinsky was planning to propose to her until after the couple was killed by a gunman in Washington, D.C., on Wednesday night.

Her parents had assumed that marriage was in the picture. Ms. Milgrim, who grew up in Prairie Village, Kan., had met Mr. Lischinsky shortly after joining the Israeli Embassy a year and a half ago to organize missions and visits by delegations. Mr. Lischinsky, a researcher at the embassy, had met her parents several times.

“He was incredible,” Ms. Milgrim’s father, Robert Milgrim, said in an interview. “He was very much like Sarah: passionate, extremely intelligent, dedicated to what he does, always on the cause of what’s right.”

A few months ago, Ms. Milgrim, 26, told her parents that she planned to travel with Mr. Lischinsky, 30, to meet his family in Jerusalem for the first time. What they didn’t know, and would only learn after the shooting, is that he had bought an engagement ring before the trip.

With the couple set to fly to Israel on Sunday, Ms. Milgrim’s mother, Nancy Milgrim, planned to travel on Friday to Washington from Prairie Village, a Kansas City suburb, to take care of her daughter’s dog, a goldendoodle named Andy.

On Wednesday night, Mr. Milgrim was getting ready for bed when news alerts on his cellphone appeared, describing a deadly shooting in Washington outside an event for the American Jewish Committee, where his daughter was a fellow. He immediately called the F.B.I. and the local police station, but neither could provide any information.