Armstrong, 23, arrived at the Garza West Unit in Beeville on Tuesday, according to the Texas Department of Criminal Justice. He was convicted of shooting his parents to death in Houston when he was a teenager in 2016.
A new defense attorney for the 23-year-old Armstrong, who was a teenager at the time of his parents' deaths, claimed in a motion for a new trial that he should have been tried as a juvenile and that prosecutors should have provided previous defense attorneys with information that questioned the credibility of a key witness.