Mapleton Police Chief John Jackson said in a statement Friday the family moved to the small town of Mapleton months ago after 45-year-old Timothy Griffith got a job in Utah.
He was found dead Thursday along with his 42-year-old wife Jessica Griffith, his 16-year-old stepdaughter Samantha Badel and 5-year-old son Alexendre Griffith. Police have said the family dog was also killed in the shooting.
They were found after one family member failed to show up for work and neighbors noticed the family cars hadn't moved. Police say authorities are doing autopsies on the bodies to learn more about exactly what happened in the home.
Officers were called to the home around 9 p.m. after neighbors reported that the family had not been seen for days but the lights stayed on and their cars had not moved.
The officers received no answer at the front door but were concerned and removed a window to get inside. Officers then found the four bodies and a dead dog that also had been shot.
Jackson did not offer details about what may have led to the killings or how they unfolded. Police did not release the identities of the family because investigators were still notifying other family members of the deaths.
The chief said the family had moved to the town a few months earlier and police had not had any prior interactions with them.
Mapleton, nestled against the mountains about 10 miles (16.09 kilometers) south of Provo, has a population of about 9,500.