A fiery helicopter crash in eastern Tennessee killed a local woman, her grown son and daughter and the daughter’s boyfriend, in addition to the pilot, authorities and relatives said Tuesday.

All five people aboard the helicopter, a single-engine Bell 206L tour craft manufactured in March 1977, were killed when it slammed into the ground at 3:30 p.m. ET Monday in Sevier County just north of Great Smoky Mountains National Park.

Pigeon Forge police identified the victims Tuesday night as the pilot, Jason Dahl, 38, of nearby Sevierville; Johna Morvant, 49, of Kodak, about 10 miles north; her daughter, Peyton Rasmussen, 22, and son, Parker Rasmussen, 18, both of Huntersville, North Carolina; and Michael Glenn Mastalez, 21, of Prosper, Texas.

Luke Schiada, a senior safety investigator with the National Transportation Safety Board, said Tuesday that preliminary evidence indicated that the helicopter hit some sort of structure on top of the ridge before it went down, leaving skid marks along the ridge.

Schiada said it was too early in the investigation to speculate on the cause of the crash, saying that because “there was a significant post-crash fire,” investigators will need as long as a year to complete their work.

Investigators haven’t had a chance to review the tour company’s records yet, he said, and the 39-year-old aircraft didn’t have traditional flight recorders on board. he said.

The helicopter, operated by Smoky Mountain Helicopters, was on its second flight of the day, which should have lasted about 12 minutes, Schiada said.

The Rasmussens had been living with their father, Scott Rasmussen, in North Carolina and were visiting their mother in east Tennessee at the time of the accident, relatives said.

Peyton Rasmussen was studying to be a medical technician, and Parker Rasmussen was a senior in high school, Scott Rasmussen told NBC station WBIR of Knoxville, Tennessee. Mastalez was his Peyton Rasmussen’s boyfriend, he said.

“They were just the light of my life and very loving kids, and I’m still in shock and disbelief that they’re not here anymore,” Scott Rasmussen said.

“It’s just really shocking right now that my kids went to go visit their mom and are never coming home.”