The interview occurred in the hours after A.J. Armstrong allegedly killed his parents, Antonio and Dawn, at their southwest Houston home in July 2016.
On Wednesday, jurors heard the 911 call A.J. made on the morning of their deaths. He told dispatchers, "It's all my fault."
But the defense argues it's not a confession. A.J.'s attorneys claim the teen later told police he meant he was sorry he couldn't stop the intruder in the house.
A.J. broke down in tears when prosecutors showed pictures of his mother shot in bed.
"The CSU expert was a textbook example of incompetence. He did not know where the alarm system was in the house, he didn't know where the sensors were. I think he testified that there might have been 5,200 sensors in there. All that stuff is not true. He had no idea regarding the vast majority of the layout of the house after being there for seven hours. That's reasonable doubt," said defense attorney Rick DeToto.
Prosecutors did not comment after Wednesday's testimony.
Big takeaways from today at #ajarmstrong trial: we heard AJ's 911 call; we saw AJ break down in court when prosecutors showed pictures of his mother, Dawn, shot in bed; we saw hard evidence like the gun, shell casings, bloody pillows. #abc13 Catch up here: https://t.co/6mEJCHXH3t— Courtney Fischer (@CourtneyABC13) April 3, 2019