BRIGHTON, Colo. -- A man and woman are accused of killing a 78-year-old Brighton man and then setting his house on fire to cover up the crime.

Firefighters found Bob Moreland's body in his home in Adams County last month after they knocked down the blaze.

Laura Childress, 37, and Chase McGraw, 18, will be charged with first-degree murder and first-degree arson, the Adams County District Attorney’s Office said Tuesday.

Investigators did not say how Moreland was killed, did not provide a possible motive, and did not say what led them to the arrest of Childress and McGraw. The suspect's relationship to Moreland was unclear.

Moreland, a widower with three adult children, lived alone, but investigators had looked into reports that some other people were staying with him, possibly people he had recently taken in.

Moreland's van was stolen during the homicide but discovered hours later. Moreland's son said his father carried a good deal of cash with him and that he had two safes in his home.

Everett Moreland described his father as a "nice guy who was always helping people."

He learned of his father's death the morning of Father's Day.

Childress and McGraw are being held at the Adams County Detention Facility without bond. They will make an initial court appearance on Wednesday.