( 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 shot and killed his wife , Wendy , and two of their children , sheriff 's officials say . 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 . '' The shootings happened in Lakeland , Florida , just east of Tampa . When the shooting began , the couple 's son , Nathan , ran out of the house and down the street -- with his dad chasing him through the garage and firing several shots , authorities said . Nathan was unhurt and will be placed with family members . Investigators do not know what led to the shooting , but believe it was preceded by `` some kind of domestic disturbance , '' a statement from the sheriff 's office said . Bellar was arrested twice in Polk County : for aggravated assault in 1994 , and for driving under the influence in 1999 . His wife was arrested in March for battery domestic violence .
Bodies of gunman , wife , 2 children found at Lakeland , Florida , home , officials say . Boy , 13 , was chased down street , fired at , but got away unharmed , officials say . Comment: