(CNN) -- A man shot and killed his wife and two of their children and then killed himself in central Florida on Sunday night, authorities said.
Troy Ryan Bellar, 34, used a high-powered rifle with a scope to shoot his 31-year-old wife, Wendy, when she tried to leave their home, the Polk County Sheriff's Office said in a statement.
Two of the couple's children -- 5-month-old Zack and 7-year-old Ryan -- also were killed, but a 13-year-old got away, with the father chasing and firing after him, officials said.
"It is beyond my understanding why a man would shoot and kill his 5-month-old baby boy, his 7-year-old baby boy, try to kill his 13-year-old son, shoot his wife and then turn the gun on himself," said Polk County Sheriff Grady Judd. "There is no explanation for that."