At the age of 9, authorities say, Randy Young watched his father shoot and kill his mother. At the age of 31, the Catoosa County man mimicked the act by gunning down his estranged wife and 14-month-old daughter Monday as they ran from him to a neighbor's home. Young, who authorities say was taking several prescription medicines to treat depression, ended the violent outburst by killing himself.

The double homicide, suicide is a grim reminder that domestic violence often passes from parent to child. Research by the Centers for Disease Control and Prevention in Atlanta reports that children who see domestic violence, or experience it from caregivers, have a higher risk of repeating the behavior as adults. Neighbors were stunned by the scene, which shattered Christmas Day festivities and the serenity of their suburban neighborhood in the Boynton Community of Catoosa County. When the gunfire ended, three people lay dying on a neighbor's lawn. Several children under the age of 6 were jumping on a trampoline in a nearby yard when the fatal shots were fired. They saw everything, police said. "It was very traumatic for one of the 5-year-olds," said Capt. Dewayne Steele of the Catoosa County Sheriff's Department. "He made the statement to us that he saw Mr. Young shoot his child and the baby drop to the ground." Steele described the killings as premeditated and execution style. The children who witnessed it told police that Nicole Young, 31, fled from her home carrying her infant daughter, Hailey. Mr. Young chased after them with a 9mm pistol. The witnesses reported that Young shot his estranged wife first and she dropped the child. The toddler stood and faced her father. Young was less than three feet away from his daughter when he shot twice. He then fired a second shot at his wife before turning the gun on himself.

All three were shot in the head at close range, Steele said.

Authorities say the couple was divorcing, and Randy Young was living with a friend in Chattanooga. More than a month before, on Nov. 4, sheriff's deputies were called to the Youngs' home after Nicole Young reported that her husband had pointed a gun at her and was threatening to shoot her in the head. In that incident, Nicole Young safely fled with her daughter to a neighbor's home - the same residence she ran toward on Christmas Day. Randy Young barricaded himself in the home, and surrendered after a four-hour standoff with police in which he threatened to shoot anyone who tried to arrest him. He was charged with simple battery and obstruction of a law enforcement officer, for which he was given a $5,500 bond. He was out on bond when he killed his family. Initially police reported that Randy Young had taken the murder weapon from his estranged wife's house. Capt. Steele now says that Randy Young stole the gun from a roommate on Christmas Day. Earlier in the day, Randy Young - exercising his holiday custody rights - drove from Chattanooga to Catoosa County where he picked up his daughter. He took Hailey back to Chattanooga and reportedly asked his roommate to buy some milk for the child, who appeared sick. When the roommate went to the store, Steele said, Young stole the firearm and drove back to his estranged wife's house. The roommate notified authorities of the theft after hearing news reports about the murder, suicide. That Randy Young drove back to the house with a gun indicates it was a premeditated act, Steele said. "He planned it," the 25-year law enforcement veteran said. "He planned to go there and kill them.