HOUSTON (KHOU) — On the outskirts of Waller, three lonely graves with temporary markers serve as permanent reminders of the town's worst day ever. But what the people who live there perhaps don't realize, is just how much worse it could have been.
"It's just one of those things you can't answer in your head," said Waller County District Attorney Elton Mathis.
"The thing about my family is I would protect them with my life, but at the same time, if anyone was going to hurt them, it was going to be me," Sesler told Rangers in a jail-house interview.
In the early morning hours of March 19, he killed his mother first in the garage and says he realized then there was no turning back.
"I was like, well…I'm already committed really. Can't really go to my brother and dad and be, like, yeah…I just killed our mom," he told troopers.
Sesler killed his brother next and then his father.
"Then he returns and does, basically for lack of a better term, mercy shots to make sure all of his family members are dead," said Mathis.
"I didn't want anyone to be suffering, lying on the floor for hours moaning and groaning, so I was, like, I've got to retrace with a more powerful weapon and shoot them again," Sesler told the Rangers.
"He didn't just kill them. He massacred them. He tore up the house he grew up in," said Waller Police Chief Phil Rehak.
Sesler few into a rage, killing every living thing in the house, including the family pets. He then began scribbling messages asking for forgiveness. One reads: God, please forgive me. I will never forgive myself.
The Rangers asked Sesler why he did it.
"They were the first immediate human targets in my sight. If I was going to go out and do anything, they would have to go," Sesler responded.
"He said it was to spare his family from what he was about to do," said Rehak.
You see, Sesler had a plan. Not even a block from his family's home is Waller Junior High School, and just hours after the killings, he found himself in the parking lot armed with an assault rifle and more than a hundred rounds.
"Right after I had killed the family, it was on my mind to do," Sesler said. "And I'm like, there's my opportunity. Go ahead. Go get ‘em."
Sesler had other things on his mind as well, including a Columbine-style shooting at Waller High School's Homecoming game.
"I was thinking I could creep across the field and open up on the home fans and probably cause more mayhem with people trying to get away and falling on each other than actual bullets," Sesler told the Rangers. "I don't think a period of two or three days ever went by that I didn't think about some sort of violent act."
So why didn't he follow through?
"Maybe it was what happened was just too real," Sesler told the Rangers.
"The scary thing about this is that Trey could be any kid in suburban Houston," said Mathis.