HOUSTON — It was 1:40 a.m. on July 29, 2016, when 16-year-old Antonio "AJ" Armstrong called 911 from his family's Bellaire-area home on Palmetto Drive.

"I just heard two gunshots in my parents' room," he told the dispatcher. "Will you please hurry?" A.J.

said he was hiding in the closet of his third-floor bedroom. "But my sister's downstairs on the second floor. She's 12.

" The teen confirmed his dad had a gun in the nightstand or under the bed in his parents' second-floor bedroom. At one point during the call, A.J.

muttered to himself, "It's all my fault." When police arrived, he ran downstairs and turned off the alarm to let them in. They went upstairs and discovered that Antonio Sr.

and Dawn Armstrong had been shot in their bed and pillows had been placed over their heads. Dawn was already dead from two gunshot wounds. Antonio Sr.

was rushed to the hospital with a single gunshot wound but doctors weren't able to save him. The killer left a note scribbled in large letters downstairs on a kitchen counter next to the murder weapon. "I HAVE BEEN WATCHING YOU FOR A LONG TIME.

COME GET ME." Investigators found no sign of forced entry. They separated A.

J. and his sister Kayra, bagged their hands for gunshot residue and put them in patrol cars. A.

J. called his older brother Josh who, according to his girlfriend, grabbed his shotgun and ran out frantically from his nearby apartment. When he got to his parents' home, Houston police officers wouldn't tell him anything or let him go .