(CNN) -- Police in Scottsdale, Arizona, said Friday that they don't know why a man fatally shot his two young sons and a woman believed to be his wife before turning the gun on himself.
The bodies had been in the family's rental home for several days before they were discovered Thursday afternoon, police spokesman Dave Pubins said in a statement.
An out-of-state relative told police that the family had been out of touch and asked them to check the residence, Pubins said.
The father was identified Friday morning as Russell Gilman, 48, and the woman was tentatively identified as his wife, Stacey, Pubins said. He said a definite identification of the woman, thought to be 45 years old, was expected after an autopsy.
The boys, who were not named, were ages 3 and 7, Pubins said.
A second police spokesman, Mark Clark, told CNN affiliate KNXV-TV that a note and a weapon were found in the home, but he didn't elaborate.
"They seemed to be very normal people, other than being quiet, no explanation, really," neighbor Wayne Lehsten said. He added that the four never participated in neighborhood activities like block parties.
"They kept to themselves," he said. "We would greet them once in a while as we saw him take the children to school."
Pubins called the deaths "a tragic event" and said there was nothing to show that anyone outside the home was involved.
A neighbor, who identified herself as Carrie, said she saw the commotion and police cars as she drove to her house.
"I have children, and that makes me sad," she told CNN affiliate KTVK-TV3.
"This is the kind of a community -- these few blocks here -- [where] people are very friendly. There are potlucks and Halloween get-togethers, so why couldn't they reach out to somebody?"