Cindy Rolow said she didn't really know the family that lived five doors away from her, but she would often see the father and son walking through the neighborhood holding hands.
"We always thought that was cute," she said.
On Friday, the father and son -- plus the mother and another child, were found dead in their Southern California home.
Authorities believe the man shot and killed his wife and two children before turning the gun on himself.
"This is just awful, it's horrific," Rolow said. "It's so sad to hear somebody would take their family's life and their own life."
Los Angeles County sheriff's deputies went to the house in Santa Clarita -- about 35 miles north of downtown L.A. -- early Friday after getting a call from someone concerned about the family, Lt. Rodney Moore said.
Found fatally shot were Michael Birnkrant, 51, wife, Amy, 47, their college-age daughter, Drew, and 11-year-old son, in what appeared to be a murder-suicide carried out by the father, KTLA reported.
Police were not looking for any suspects.
According to investigators, the family members were found shot in the chest, with the gun discovered close to Michael’s body.
The house is in a neighborhood of modern, two-story homes in a development below the foothills of the Angeles National Forest.
The Associated Press contributed to this report.