The witness statements of a 16-year-old boy were heavily scrutinized when up against the damning evidence of his parents’ double homicide.

Antonio “A.J.” Armstrong Jr. faced three separate murder trials when Texas authorities accused him of gunning down Dawn and Antonio Armstrong Sr. as they slept, as featured in Season 2, Episode 6 of Prosecuting Evil with Kelly Siegler. Despite the teen’s contradictory statements, data taken from the home alarm system, and a mountain of circumstantial evidence, many — including members of the Armstrong family — spoke out against the state’s filing of capital murder charges.

“The fact that one of the victims was a former NFL player, along with his beautiful wife, I’m wondering, ‘Why did that happen?’” Siegler said. “But when the family’s perfect façade starts to crumble away, and the fingers start getting pointed at somebody else in the family, everything starts to come crashing down.”

Dawn and Antonio Armstrong’s 2016 double murder

On July 29, 2016, at around 1:40 a.m., Armstrong Jr. called 911, reporting that he heard gunshots downstairs in his parents’ bedroom of their shared Houston home. He stated to dispatchers his father typically kept a firearm in his nightstand drawer and that his 12-year-old sister was still asleep inside the residence.

“How’d you get into our house?” Armstrong Jr. was heard saying while still on the line with 911 operators. “It’s all my fault.”

Authorities helped Armstrong Jr. and his sister out of the house before the teenage son placed a call to his older half-brother, Josh Armstrong, who lived in an apartment down the street.

Inside the Armstrong home, investigators found the parents shot in the bed of their master bedroom, located at the top of the stairs. Dawn Armstrong was already dead, and Armstrong Sr. was found with a pillow over his face, according to Jason Williams, an E.M.T. with the Houston Fire Department.

“I took the pillow off, and he’s still alive, and we go to pretty much fight or flight mode at this point,” Williams recounted. “He has blood everywhere, and you can see the entry wound from his gunshot wound to the head. So, he’s in bad shape.”

Armstrong Sr. was rushed to a hospital and placed on life support but succumbed to his injuries hours later.

At the crime scene, Houston Police Department (H.P.D.) officials recorded several unusual details. A bullet hole in the ceiling just outside the couple’s bedroom was proven to have been shot from Armstrong Jr.’s third-story bedroom, with the bullet embedded in the floor. Furthermore, in the kitchen, police found Armstrong Sr.’s handgun on the counter and a scribbled note that read, “I have been watching for a long time.”

“That only adds to the mystery, ’cause who would want Dawn and Antonio Sr. dead?” Siegler wondered.

According to the Prosecuting Evil host, Armstrong Sr. and his wife were well-known in the community; their children even attended the same private school as Siegler’s daughters. The murdered father was not only a former linebacker for several NFL teams (including the San Francisco 49ers and Miami Dolphins), he also owned gyms in the Houston area.

Harris County Assistant District Attorney John Jordan said they were “the kind of folks you want to be jealous of, but nobody could because they’re so darn charismatic.”

Police look into 16-year-old Antonio “A.J.” Armstrong Jr.

H.P.D. detectives questioned all three Armstrong children and quickly cast their suspicions onto Armstrong Jr., who claimed he got up in the middle of the night to use the restroom and heard the door to his parents’ bedroom, followed by the sounds of two gunshots. He allegedly ran upstairs, just seeing a masked man run from the master bedroom.

“In a 16-minute 911 tape, he never mentions that there is a masked man in the house,” Jordan told Prosecuting Evil. “Then, hours later in a statement, said, ‘Oh, there was a masked man in the house, and I saw him running.’”

When asked about the bullet hole in the ceiling, Armstrong Jr. claimed he and a friend — weeks before the double murder — played with his father’s gun without the father’s knowledge and shot the firearm through a couple of pillows, hoping it would silence the blast.

Armstrong Jr. admitted to police that he deactivated the house alarm for responders, which rang peculiar to detectives because any purported intruder surely would have tripped the alarm while breaking in. Plus, there were no signs of forced entry.

The teen maintained, “I had nothing to do with this,” as recorded in his taped interview.

Armstrong Jr. was eventually charged with capital murder and booked into a juvenile detention center.  

Prosecutors build a case against A.J. Armstrong

Armstrong Jr. retained defense attorney Rick DeToto, and after the case was reassigned to adult court, he posted bail and was released to his paternal grandparents. Prosecutors worked to build the case against the teen, pointing to the junior’s “volatile” relationship with his parents, according to Assistant District Attorney Ryan Trask.

Relatives and loved ones, including half-brother Josh Armstrong, fiercely supported the defendant. The case became big news, partly because of Armstrong Jr.’s age and the father’s profession.

As part of their investigation, H.P.D. reviewed texts between Armstrong Jr. and his parents that illustrated steady discord in the days leading up to the murders. Dawn and Antonio Armstrong Sr. frequently texted their disappointment over the teen’s alleged drug use, persistent lying about his whereabouts, and not obeying general rules.

“It was a boiling pot from with inside the four walls of that house,” Trask told Prosecuting Evil.

Investigators looked at the bullet hole that came from the teen’s bedroom and through the ceiling, citing it as a test shot sometime before the night of the murders. They also took note of a long but narrow burn mark in the carpet at the top of the stairs, created by fire and the same kind of gasoline found in a rubbing alcohol bottle inside Armstrong Jr.’s bedroom.

Prosecutors believed the location of the attempted arson was a means of trapping the parents inside their burning home.

“AJ CAUGHT THE HOUSE ON FIRE,” Dawn Armstrong texted her son, Josh. “We stopped it. He is lying.”

The defense proffers an alternate suspect

Defense attorney DeToto and co-counsel believed there wasn’t enough motive, and the number of supporters suggested so. Instead, they said Josh Armstrong — who lived with depression following the murders — made for a better suspect.

He was, however, never deemed an official suspect by police.

“Josh recently had found out that Antonio was his stepdad,” DeToto told Prosecuting Evil. “According to the family, there was some jealousy with Josh, the way they were treating A.J., and the way they were treating Kayra [the younger sister], and how he felt he was kind of the black sheep of the family.”

Josh Armstrong’s girlfriend, Hannah Pilon, was with Josh on the night of the murders and served as his alibi.

“Before the murders, Josh was not rejected by his family by any means,” Pilon insisted. “They spoke every single day. They loved Josh, and Josh loved them. That was his real dad to him.”

The trial began on March 29, 2019, and prosecutors argued that Armstrong Jr. killed his parents after they punished him by taking away his car and phone and preventing him from seeing his girlfriend, all the results of his flunking out of school. They also highlighted the burn mark at the top of the stairs and the alleged test-fired shot.

Although the jury believed Armstrong Jr. was guilty of the murders, they struggled to send someone as young as the defendant to prison for the rest of his life, according to prosecutors. On April 24, 2019, the jury was deadlocked, with eight voting guilty and four voting not guilty.

The state would get a second chance.

The second trial of A.J. Armstrong begins in 2022

Ryan Trask and John Jordan prosecuted Armstrong Jr. in the second trial, which began in October 2022 after COVID-19-related delays.

“It’s now three years later when the second trial is happening, and in that time, A.J. Armstrong has grown up,” Siegler said. “He is now married to his long-term girlfriend, Kate. He has a son of his own; he looks a lot older. This is gonna be a whole different kind of appearance that he portrays in front of a jury this time compared to last time.”

Armstrong Jr. came backed by a sizeable number of supporters, listening as prosecutors focused on his actions leading up to the murders, his contradicting statements to police, and the data taken from the home alarm system. However, new evidence and expert testimony helped the defense find a minimum of 77 errors related to the software of the security system — information not heard in the first trial — such as doors of the residence opening and closing simultaneously.

For trial number two, the defense “put all their cards in” that Josh Armstrong — who had mental health issues — made for an alternate suspect, according to Trask.

“It’s interesting, ’cause it’s the only case I ever tried in my career where we had to essentially be a prosecutor and a defense attorney in the same trial,” Trask told Prosecuting Evil. “We were fighting to convict somebody we know is guilty, and at the same time, fighting to exonerate someone we know is innocent.”

Despite all parties’ best efforts, the trial ended with another hung jury; this time, four for guilty and eight for not guilty. It was a “devastating” result for Trask and Jordan.

DeToto said the decision brought “a groundswell of support” for Armstrong Jr., including numerous social media posts and banners on major roadways. Many believed two deadlocked juries were enough and that the defendant should not be tried again.

But prosecutors persisted.

The third and final trial of A.J. Armstrong

This time, Jordan remembered being “a young prosecutor” in the courtroom when Siegler successfully tried the case of Susan Wright, which served as the very first episode of Prosecuting Evil. In Wright’s case, Siegler had a bed constructed in the courtroom to effectively show jurors how Wright viciously stabbed her husband after tying him down.

Prosecutors decided to take the same approach and built an actual-sized staircase matching the one inside the Armstrong residence, from where the defendant claimed he saw a masked man running from his parents’ bedroom. With the help of crime scene reconstruction expert Sgt. Celestina Rossi of the Montgomery County Sheriff’s Office, authorities erected a staircase using precise measurements and hauled it before the jurors’ box.

They later brought in a mock bedroom to provide a visual sense of the crime scene.

The third trial began on May 1, 2023, and not only did prosecutors successfully show the jury how close Armstrong Jr. would have been from to purported assailant — just three feet, three inches, according to Jordan — but they conveyed that Armstrong Jr. made no mention of the masked man when calling 911.

Furthermore was the notion that someone snuck inside and killed the couple with Armstrong Sr.’s own firearm.

“They would have to come into the bedroom, walk around the king-sized bed over to the nightstand, go into the bottom drawer, remove the firearm, assume that it’s loaded, come back around to Dawn’s side of the bed, and fire four shots in the middle of the night,” Rossi told Prosecuting Evil. “I thought that was impactful.”

Prosecutors also returned to the security system data, adding new software experts on the stand, and referred to texts between Armstrong Jr. and his mother.

“The alarm doesn’t lie, YOU lie,” Dawn texted her son months before the murders.

On August 15, 2023, the jury found Antonio Armstrong Jr. guilty of capital murder and sentenced to life in prison. Because he was 16 when the crime occurred, he will be eligible for parole after serving 40 years.

Although a guilty verdict signaled victory for those siding with his guilt, many continue to fight for Armstrong Jr.’s innocence.

“It was the worst moment of my career,” DeToto said of his client’s conviction. “It’s a complicated emotion in that I know I fought my ass off for him. I gave a lot for that young man, but I still feel like I let him down.”

Don’t miss all-new episodes of Prosecuting Evil with Kelly Siegler, airing Saturdays at 8/7c on Oxygen.