AJ Armstrong trial: What we know about teen accused of killing parents

Witnesses took the stand in the case of Antonio Armstrong Jr., who is accused of killing his parents. (KPRC)

HOUSTON – The defense continues its case Monday in week four of the trial of a Houston man accused of killing his parents.

Prosecutors say Antonio “A.J.” Armstrong Jr., 19, shot his parents in July 2016. The shooting occurred at the family’s home in the 5300 block of Palmetto Street in southwest Houston.

Dawn and Antonio Armstrong Sr. were asleep in their bedroom when they were shot. Armstrong Jr., who was 16 years old at the time of the shooting, maintains his innocence.

Armstrong Jr. said there was a masked person in the house, according to audio of the 911 call he made to police. His defense team supports that claim, alleging Houston police hastily zeroed in on Armstrong Jr. before conducting a thorough investigation of the murder scene.


Armstrong Jr. was the middle child of Dawn Armstrong and Antonio Armstrong Sr.

Armstrong Jr. was a star athlete at The Kinkaid School, where he played football and was considered a “standout” by the coaching staff.

“He had a lot of confidence in his ability,” testified Stephen Hill, former head football coach at Kinkaid.

However, during his junior year, Armstrong Jr.'s athletic success became overshadowed by slipping grades and tension between him and his parents, testimony alleged.

Armstrong Jr. was charged with murder hours after his parents’ death. He is accused of using his father’s gun, a .22 caliber pistol, to shoot them.

Police said they found the gun next to what appeared to be a note on a kitchen counter.

A.J.’s fingerprints were not found on the gun. Moreover, there was no trace of his DNA on the gun, the note, the notepad or the pen used to write the note. His hands and clothing tested negative for gunshot residue.

A witness for the prosecution testified the gun used could have been fired without extracting a compound of three elements known as gunshot residue.


Twenty-eight witnesses testified for the prosecution, which rested its case April 18. A central part of the prosecution's case rests on the belief that A.J. Armstrong had to kill his parents. The alarm system indicated no one entered or exited the home leading up to and following the shooting.

Moreover, a sensor on the second floor, near Dawn Armstrong and Armstrong Sr.'s bedroom, recorded movement between the third and second floor roughly 30 minutes before A.J. Armstrong called 911 to report an intruder in the home.

A.J.'s bedroom was on the third floor of the family's townhome on Palmetto Street in southwest Houston.

The home’s alarm was administered by ADT.  An administrator from ADT offered expert testimony for the prosecution, claiming the alarm system was reliable and acted without error the night of the shooting.

Two key moments bookend the prosecution’s case: the presentation of a 911 recording and message transcripts. Earlier in the trial, jurors heard audio recordings of the interrogation session between Armstrong Jr. and Houston police, who the prosecution said zeroed in on A.J. Armstrong shortly after arriving at the scene.

They also read text and email transcripts between Armstrong Jr. and his parents. While tens of thousands of pages of communications were extracted, prosecutors highlighted what they argued supported their claim that A.J. Armstrong had become a problem for his parents.

The messages extracted spanned from October 2015 through July 2016, stringing together a narrative a troubled teen who was failing classes, skipping tutoring sessions and lying to his parents about it all.

Dawn and Armstrong Sr. grew increasingly frustrated with their son, the messages showed.

However, Armstrong Jr.’s defense argues the transcripts don’t provide a character sketch of a killer; rather, they show “cherry picked” exchanges between a 16-year-old and his parents. Thus, said the defense: prosecutors are trying to get A.J. Armstrong convicted of murder on no more than circumstantial evidence.


Armstrong Jr.'s defense team argues Houston police pegged A.J. Armstrong as the killer before officers concluded an investigation at the home. Rick DeToto, Armstrong Jr.'s defense attorney, said police placed too much emphasis on the alarm system, claiming officers jumped on A.J., without properly investigating the alarm system.

A separate alarm system expert testified for the defense Thursday, claiming the alarm system at the Armstrong residence was not properly installed, including sensors on windows. Jim Parker also testified that motion detectors on the first and second floors were not reliable.

Parker concluded either “the motion detectors are not reliable, they were not working properly or there were multiple people in the house," claiming there’s no way Armstrong Jr. could have called 911 while running around the house at the same time, as the motion detectors suggest.

The fourth witness for the defense is expected to be called to the stand Monday afternoon.

About the Author:

Emmy and Edward R. Murrow award-winning journalist. NOLA born and bred, though #HoustonStrong, with stops in Minnesota, New York, Massachusetts, and Connecticut in along the way.