Elaine Keesick says her brother and his family were the first people on the scene when a small aircraft crashed into a frozen lake outside a northern Ontario reserve Tuesday morning, killing four out of the five people on board.

"My niece, I think she is traumatized. She said she could hear them shrieking in the plane but they couldn't save them because of the fire," said Keesick, the director of education on the North Spirit Lake native reserve, where the Keystone Air charter plane crashed Tuesday.

The craft hit the lake just across from Keesick's brother's house on North Spirit Lake and the flaming wreckage was visible from his home, she said.

Keesick said she saw people bringing in the bodies from the wreckage and treating the lone survivor at the local health clinic.

"They said they were doing what they could to stabilize him," she said. "He was shaking."

Officials have not released any information about the victims, but Keesick said she believes all the passengers on the plane were members of the local band council or the Winnipeg-based Aboriginal Strategies Inc. She identified three victims as Martha Campbell, Ben Van Hoek and Collette Eisinger.

The Aboriginal Strategies website lists Van Hoek as the president of the organization and Eisinger as an accountant. According to the band council website, Campbell was the community's health director.

The plane, a Piper PA-31 Navajo, left Winnipeg around 7:15 a.m. local time destined for North Spirit Lake and crashed about a half-mile from the runway around 10 a.m., Peter Hildebrand, regional manager of air investigations with the Transportation Safety Board, said from Winnipeg.

At this point, it's too early to speculate on what might have led to the crash, he added.

The Transportation Safety Board is sending investigators to the scene, however they likely won't arrive in the remote community until Wednesday.

A man answering the phone at the Manitoba-based airline confirmed the crash, but could provide no details. A message to the company's spokesman was not immediately returned.

North Spirit Lake is a fly-in reserve about 455 kilometres north of Kenora, Ont.