PHOTOS: Oak Lawn fire
The victims have been identified as John Conta Sr., in his 60s; his wife Janice Conta, 68; their son John Conta Jr., 36; and their grandson Matthew Meier, 5. Police say Conta Jr. shot the other three, set a fire, then killed himself in the garage.
Police say the boy, who was the shooter's nephew, had a birthday party at his grandparents' house the day before the fire. Police say something said at the party may have upset the shooter. The small boy stayed at his grandparents for the night after the party. He was the son of the shooter's sister.
"The grandparents adored him, so the mom left the 5-year-old with the grandparents, and unfortunately something tragic happened in that house. I don't know if we'll be able to fully understand why," said Michael Kaufmann, Oak Lawn chief of detectives.
Police say the shooter spent a year in Russia potato farming, but returned in recent years and lived with his parents. He had no known job since his return. Family members told police the man had changed when he returned, possibly indicating mental health issues.
Authorities say the fire was set in the home's basement in a corner with an accelerant. A gas can was found, police said.
Around 5 a.m. Wednesday, emergency crews were called to the home in the 9800-block of 51st Avenue because of the fire. A firefighter on his way to work went straight to the address.
"He encountered a vehicle inside the garage and heard noises coming from the vehicle. At the time, he approached the vehicle and opened the door and observed an adult male in the driver's seat take his own life with the use of a shotgun," Oak Lawn Police Chief Mike Murray said.
The body of John Conta Sr. was found just inside the home. Hours later, after the fire was struck, officials found the bodies of the woman and 5-year-old in the rubble.
Police say a safe containing about ten firearms was found in the home. John Conta Sr. was a hunter, police said. Police say the boy's mother is accounted for and is devastated.
"When his daughter bought a home in Oak Lawn, he called me about the insurance. Yesterday, he called me to make a payment on her homeowner's insurance. We became friends over the years," neighbor John McNicholas said of John Conta Sr.
The shooter's retired parents volunteered at St. Linus parish.
"We're all devastated about this news as everybody is because we knew them and we knew them to be such fine people," said Father Gene Smith, St. Linus parish.
The fire chief said frozen hydrants and slippery conditions hampered firefighters, but the fire was struck four hours after it began. The fire led to a roof collapse. Firefighters had to bring in heavy equipment to help in the search.