5 year old Chicago area boy shot in domestic shooting

A domestic shooting rampage took the life of a 5 year old Illinois boy on his birthday, along with 3 members of his family:

Matthew Meier was celebrating his 5th birthday by spending the night with his grandparents John and Janice Conta in Oak Lawn. What happened next authorities can't explain.

Sometime overnight, Matthew's uncle John Conta Jr. shot all three dead. He also poured gasoline in the basement and lit it, according to police and fire officials.

Autopsies conducted today determined that all of the people died from shotgun wounds. After shooting his family members, Conta Jr. committed suicide by shooting himself in the face, according to the Cook County medical examiner's office. 

One of the first firefighters on the scene Wednesday morning entered the garage of the home in the 9800 block of South 51st Avenue as Conta Jr. pulled the trigger of a shotgun and killed himself too, police said. 

“What made him go into this rampage, I don’t know if we’ll ever know that,” said Oak Lawn Police Division Chief Michael Kaufmann. 

Conta Jr. had spent about a year working as a potato farmer in Russia before moving back with his parents a few months, police said. 

“When he came back, he seemed a little different,” Kaufmann said. “His mental state may have changed.”