A 95-year-old woman and her 68-year-old son were killed early Friday morning in an Arvada house fire reported by a neighbor who smelled smoke but couldn’t see a fire, authorities say.

The Jefferson County Coroner’s Office identified Lorraine Cowan and Stephen Ringenberg as the fire victims.

Firefighters responding to a 2:50 a.m. 911 call about a smoke odor near 64th Avenue and Lee Street searched the neighborhood until they saw fire and smoke coming from a window, said Michelle Cherniske, spokeswoman for the Arvada Fire Protection District.

Firefighters immediately entered the home and carried the woman and her son out of the home, Cherniske said.

“Someone who lives behind the home woke up to a smell,” she said.

Firefighters tried to revive Ringenberg, but were not able to do so, she said. Cowan was taken to a hospital, but was later pronounced dead.

The fire started in the home’s basement. Investigators are trying to determine the cause of the fire.

Six fire engines and three medic units responded to the blaze, which was mostly contained in the interior of the home. The outside of the home remained largely intact.

Cherniske said that 95 percent of bad odor calls don’t turn out to be house fires. In this case, firefighters kept searching until they found the burning home, she said.

“It doesn’t appear like there is any suspicious activity,” Cherniske said.