Alaska State Troopers are investigating a fire that burned down five structures on Sunday on a family's property north of the Interior community of Grayling.

Rachel Freireich, Grayling's tribal administrator, said a team of Grayling firefighters had been flying to Galena on Sunday, on the way to an out-of-state assignment, when they flew over the cabins and saw the fire.

The structures were located about 40 miles north of Grayling on the west bank of the Yukon River, near Blackburn Creek. Josephine Thurmond, one of the cabin owners, said she got a call early Sunday evening about the fire.

"It's heartbreaking. Just a lot of history up in smoke," Thurmond said from Anchorage.

Her brother in Galena, Darryl Thurmond, said the property has been in the family for five generations.

Thurmond visited the cabin "springtime, summertime, fall time, every chance we get, that's where my vacation is at," he said.

A main cabin, guest cabin, greenhouse, warehouse and generator house were all burned, Thurmond said.

Undamaged in the incident were an older cabin, built in the 1930s or 1940s by Thurmond's father, and the family's smokehouse.

The family also has a private cemetery on the property. Thurmond said he planned to travel 180 miles from his home in Galena to the check the condition of the graves this weekend. He wasn't sure whether the family would try to rebuild the cabins.

On Sunday, Freireich said by the time people arrived on scene, the buildings were destroyed but still smoldering. Left behind at the scene were several threatening and racist notes toward Alaska Natives, Freireich said.

Alaska State Troopers confirmed Monday that they are investigating a report of fire-damaged structures north of Grayling, but did not have any other immediate information.

Spokesperson Megan Peters said troopers were coordinating a response to the site of the fire.

Grayling is a community of about 200 people on the Yukon.In July, three cabins were burned down along the Yukon north of Galena in an incident that investigators called "suspicious."