Victoria Kong’s family was concerned about her growing memory loss and confusion, so they planned to have the 83-year-old grandmother checked out by doctors after she returned from Barbados, relatives said.

But when her flight landed at Reagan National Airport on Friday evening, surveillance video shows that the Gaithersburg woman walked past an American Airlines agent sent to escort her to her waiting daughter. She walked out of the airport and vanished.

Searchers discovered the woman’s body in a wooded area near Gravelly Point on Monday after an extensive three-day search using police, volunteers, a helicopter and a boat, the U.S. Park Police said. The woman’s death prompted clashing accusations from the family and the airline about whether enough had been done to safeguard her travel.

“It is a nightmare,” said Joy Anderson, Kong’s daughter. “I kept saying at the airport it’s crazy my mother is missing and no one is doing anything.”

The family contends that American Airlines failed to pick up Kong from her seat on the plane, as they say they requested.

The airline said that it was never informed of Kong’s impairment and that the family asked for wheelchair service only from the gate, not from the plane. The airline said that it contacted one of Kong’s granddaughters a few days before the flight to see whether Kong needed additional help and that the granddaughter declined. A spokeswoman said the airline turned over information about that conversation to authorities.

“As a matter of policy, we reached out . . . to see if [Kong] needed help deplaning and she said no,” said American Airlines spokeswoman Stacey Frantz. “We did everything according to policies and procedures for a customer in this situation.”

Kong, who was remembered as an avid cook and a prayerful Catholic, was last seen on surveillance video leaving National about 6:30 p.m., roughly 21 / 2 hours after her flight arrived from Barbados via Miami.

A police dog twice tracked the woman’s scent from the airport up the Mount Vernon Trail to Roosevelt Island, said Rob Yingling, a Metropolitan Washington Airports Authority spokesman. That’s a distance of more than four miles.

The woman’s body was discovered just north of the airport off the George Washington Parkway about 30 feet from a bike trail, so it’s unclear whether she indeed went to the island or perhaps got there and doubled back. Authorities did not release a cause of death.

Kong, who had been in Barbados visiting one of her four children, had been experiencing cognitive problems in recent weeks that “seemed to be developing quite fast,” said her granddaughter, Alexandria Anderson.

Anderson family members said they were concerned about Kong’s ability to travel, so they arranged a wheelchair service through American Airlines to deliver Kong to and from her seat on each leg of her journey. They said that they told American Airlines officials that Kong was occasionally confused.

On Friday, they said, the system appeared to be working. They said that they received calls from an American Airlines agent who said Kong had been helped onto her flights in Barbados and Miami, where Kong had a layover.

Kong arrived at National on American Airlines Flight 1049 about 4 p.m. Friday, the Andersons said. Joy Anderson, Kong’s daughter, had her hair done especially for the occasion and arrived at National a half-hour early in anticipation of her mother’s arrival. She waited at the baggage claim area.

The Andersons said surveillance video shows Kong at the gate, walking past an agent with a wheelchair and an electronic sign with her name on it. They said Kong may have missed the agent because she had poor eyesight or may have been confused about who was picking her up.

Meanwhile, Joy Anderson waited, thinking everything was fine.

“Twice officials told us my mother was in the agents’ custody,” Joy Anderson said. “They even said whoever has her has taken her to the lavatory.”

In retrospect, Anderson said key minutes were slipping by that she could have used to find her mother. As time passed, Anderson said, she grew increasingly agitated about her mother’s whereabouts.

She said she talked to American Airlines officials, who she said seemed uninterested. She said she talked to a Transportation Security Administration official and then a guide at an information booth. It wasn’t until about 6:30 p.m. that she discovered Kong was missing, Anderson said. Authorities said they began searching for Kong immediately.

Frantz said the Andersons were mistaken in thinking airline officials told them that their mother was in the custody of an agent after the flight arrived at National.

She said American officials were saddened by the situation and were working with investigators.