Father's blood found on AJ Armstrong, DNA expert testifies at 3rd trial

HOUSTON, Texas (KTRK) -- How did blood end up on the back of the nametag sticker put on A.J. Armstrong hours after his parents were shot to death seven years ago, and whose blood is it?

Questions about the recently discovered blood evidence dominated day seven of Armstrong's third capital murder trial.

Celestina Rossi, a blood spatter and crime scene reconstruction expert, discovered the blood on June 2, 2023, days before Armstrong's third trial was supposed to start, when she went to the HPD's property to view the bloody pillows collected from Antonio Sr. and Dawn Armstrong's bed.

Rossi told the jury that when she was given the list of all the Armstrong evidence while in the police property room, she noticed Armstrong's T-shirt, pants, and sandals had been collected.

"I wanted to take a look," Rossi told jurors because, she said, she knew HPD and the Houston Forensics Science Center don't employ their own bloodstain pattern analyst.

Rossi said when she laid out Armstrong's gray T-shirt, she "immediately saw what appeared to be an almost reddish, brown stain touching the bottom of the police sticker."

Upon further testing of the blood, Courtney Head, with the Houston Forensics Science Center, confirmed the blood is "very likely" from Antonio Armstrong Sr.

Rossi testified that when she received the shirt, part of the police nametag appeared to be peeling, revealing the first stain. She conceded on the stand that the stain could be from cross-contamination.

"Pieces of blood have chipped off all over the place," defense attorney, Rick DeToto, said while holding up the two bloody pillows taken from the Armstrong bed.

DeToto showed jurors flakes sitting at the bottom of the evidence box that housed them.

But, Rossi said, she then discovered a second stain when she peeled the sticker further. The stain appeared to have been "preserved" in the center of the HPD badge, she said.

"If it was a (blood) flake from the box, if it was cross-contamination, there would be more fibers or blood flakes in the path (on the badge)," Rossi testified. "That is a pristine sticker where we see no other evidence."

HPD officers previously testified that an orange visitor sticker had been put on Armstrong while he was in handcuffs after arriving at police headquarters to be interviewed on July 29, 2016, the morning of the double homicide.

There are no corresponding blood stains on the T-shirt itself, DeToto pointed out.

Furthermore, Head told the jury that when initial DNA testing was done on Armstrong's T-shirt, pants, and sandals in 2016, there was no blood detected on any of the items.

After analyzing the size and shape of the second blood stain, Rossi said it appeared to be caused by "expiration," meaning, as Antonio Sr. fought for his life, Rossi explained, he could have exhaled the blood.

Prosecutors theorized that Armstrong shot both parents as he stood behind Dawn. Then, they say, the then-16-year-old walked around the front of their king-size bed to Antonio Sr.'s side and placed a pillow over his father's head. If Antonio Sr. had been gasping or breathing heavily, Rossi explained how expiration blood can dry in the air, similar to dust. It may have landed on Armstrong's face or hair, fallen down, and been preserved behind the badge, she testified.

"But you don't know the environmental factors of the Armstrong house to determine if the blood dried exiting Antonio Sr.'s mouth?" DeToto asked Rossi, to which she said she did not.

The defense also pointed out several HPD officers previously testified seeing no blood on Armstrong's face, hair, or clothing the morning of the murders.

This wasn't the only theory Armstrong's team attacked during Rossi's day and a half of testimony.

With her knowledge of crime scene reconstruction, on Monday, prosecutors introduced a life-size replica of part of the Armstrong staircase that led from the second to the third floor. On Tuesday, the staircase returned.

During his police interrogation, A.J. Armstrong told HPD detectives when he got "four or five stairs down" from the third floor to the second floor on his way to get medicine, he heard shots come from his parents' bedroom.

"I kind of looked, you can peek, and I saw someone," Armstrong told the officers.

Armstrong says he saw a "Black man," about 6 feet tall, wearing a ski mask revealing only the shooter's eyes and mouth.

By reconstructing the height of the stairs and measuring the narrow 3 feet 3 inches width of the Armstrong hallway, prosecutors attempted to show the jury A.J. Armstrong would have gotten a good look at the shooter, or the shooter would have seen Armstrong.

DeToto had the courtroom go dark, similar to what he said would have been a "pitch black" house, as he tried to prove Armstrong wouldn't have gotten a good look at the shooter.

"Well, I think that is a made-up story," Rossi said on the stand.

So far, 21 witnesses have testified over the past seven days. The testimony on science appears to be done, and the state could rest its case as early as Wednesday.

The trial is anticipated to go into next week.

For updates on AJ Armstrong's trial, follow Courtney Fischer on Facebook, Twitter and Instagram.