Fairfax County police identified the victims as Albert Peterson, 57, Kathleen Peterson, 52, and their children Matthew, 16, and Christopher, 13, who were all found shot to death in the family's home Tuesday afternoon, The Washington Post reported.
Neighbors said they hadn't noticed anything unusual about the family in recent months, with barbecues, sports and relaxing on the porch said to have been common sights at the home.
The Post said county court records show the couple had lived in the home for nearly 30 years, and there were no signs of legal or financial problems.
Both parents worked in technology-related areas, the newspaper said, adding family members it contacted declined to comment.
Classmates Wednesday began mourning the deaths of the two teenagers.
Police found the bodies after responding to a concern that one parent had not come to work Monday or Tuesday, WRC-TV, Washington, reported, adding the boys were not in school either day.
The TV station said students at Westfield High School, where Matthew was a sophomore, held hands in a long chain outside the building. Christopher was a student Rachel Carson Middle School.
Friends and schoolmates were posting their memories and sharing their feelings on Twitter.
"I cry as I write this because I know I will never get to see your smiling face again," one classmate wrote.