( CNN ) -- A young man who was 14 when he shot and killed his family on a New Mexico ranch owned by newsman Sam Donaldson has been freed , a spokeswoman for the state 's youth and families agency said Saturday . Cody Posey had just finished the eighth grade when he was arrested on July 7 , 2004 , in connection with the slayings of his father , stepmother and stepsister . He confessed to the slayings , but said he snapped after years of physical and psychological abuse . He said he fatally shot his father , Paul Posey , 34 , stepmother , Tryone Posey , 44 , and stepsister , Mairlea Schmid , 13 , and then used a backhoe to bury their bodies inside a manure pile . Posey was convicted in February 2006 of voluntary manslaughter for his father 's death , second degree murder for his stepmother 's death and first degree murder for his stepsister 's death . The state asked the court to impose the maximum adult sentence , life without parole . But Judge James Waylon Counts ruled that it was possible Posey could be rehabilitated and sentenced him as a juvenile offender . Once he reached 21 , he could no longer be held as a juvenile and was free to go . Posey turned 21 on Saturday , according to his uncle , Carl Clees . `` He has a bright future . I see no problems with him progressing and getting on with his life like the rest of us , '' Clees said . Romaine Serna , spokeswoman for New Mexico 's Children Youth and Families Department , confirmed Saturday that Posey is a free man . While in custody , Posey obtained his high school degree and completed nearly two years worth of college credits , Clees said , adding that he had no disciplinary issues and served as a mentor to other youths . The Posey family lived and worked on the Chavez Canyon Ranch in Hondo , New Mexico , owned by Donaldson , a former anchor at ABC News . It was Donaldson who discovered the bloody scene inside the Poseys ' home on July 6 . Donaldson was the first witness to testify at Posey 's trial in Children 's Court in 2006 . Posey 's defense called 40 witnesses , including ranch hands who claimed they witnessed years of physical and psychological abuse by Posey 's father . Testifying in his defense , Posey described the night before the shootings . His father and stepmother summoned him to the master bedroom and tried to force him to have sex with his stepmother , he testified . When Posey refused , his father burned him with a heated metal rod , he testified . Posey said he ran from the room . He was still reeling from the encounter the next morning when his father slapped him while he was doing chores . He said he decided to grab a gun from Marilea 's saddle bag , and then shot each member of his family in the head . `` I was thinking my world would be better and the whole world would be better without him , '' he told police shortly after his arrest . In his confession , Posey admitted that after burying the bodies in the manure pile , he tried to stage the scene to look like a burglary . He said he took the family 's pickup and visited friends , where he spent the night , lying about where his family was . Donaldson told jurors he called the police soon after finding a large amount of congealed blood in the house and a `` disturbing , red , dry swath '' across the floor where the bodies had been dragged . The bloody trail and backhoe tracks led police to the manure pile where the badly decomposed bodies were discovered . Although the shootings occurred within seconds of each other , the jury returned different verdicts for each victim , siding in part with Posey 's claims of abuse . But now , Posey just wants a fresh start , his uncle said . `` I 'm excited for him . I look forward to helping him as much as possible , '' Clees said . CNN 's Emanuella Grinberg contributed to this report .
Sam Donaldson was 2004 when he killed his father , stepmother and stepsister in 2004 . He said he snapped after 2004 of physical and psychological abuse . Prosecution sought life without parole , but judge said he could be rehabilitated . The Hondo ranch where the killing took place is owned by newsman Cody Posey .