Jonathan Scifres had no explanation for why he burned his 74-year-old landlady to death in her Pelican Bay mobile home last year.
"All I know is there was something wrong with me," Scifres scrawled in a handwritten letter to state District Judge Mike Thomas several months after his arrest, "and it's definitely not in me to hurt or want to hurt this lady."
Friday, Scifres, 29, was sentenced by Thomas to 42 years in prison after agreeing to plead guilty to murder in the death of Catherine Davis.
"After consulting with Mrs. Davis' family, we reached an agreement that provides some closure for them, while ensuring this offender will be off the streets of Tarrant County for many years to come," prosecutor Brock Groom said in a statement Monday.
Scrifes' attorney, Danny Pitzer, was not immediately available for comment.
Scifres, according to an indictment in the case, doused Davis with a "combustible liquid" and set her on fire inside her home in the 1500 block of Lark Court on April 18, 2016.
Authorities found her dead in the bathroom after the fire was put out. Her death was ruled a homicide, according to the Tarrant County medical examiner's office.
At the time of his arrest, Scifres "clearly appeared to be under the influence of an illegal substance," Pelican Bay Police Chief Robert Porter said.
Court records show that Scifres intended to raise an insanity defense in the case, though a psychiatrist ruled him competent to stand trial.
In a motion to examine his competency, Pitzer wrote that Scifres "said he wasn't in right mind at the time."
In the letter written to Thomas last July, Scifres pleaded for mercy.
"I didn't know how to convince you that I would never hurt this lady or simply do anything that would end me up in here," Scifres wrote from jail.
Scifres explained that he had been in trouble before and that "it doesn't make any sense" why he would hurt someone and have to go back to jail.
Scifres had prior misdemeanor convictions in Tarrant County for criminal trespassing and making a terroristic threat, according to court records.
Scifres wrote, "I believe in God and he's changed my life over the past few years."
On the day Davis died, "I didn't know what was happening, I promise," Scifres wrote.
He said he went to Davis' trailer and "told her I knew something was wrong with me ... ."
"I don't really know what happened, judge," Scifres wrote.
"I hope that you get this letter and read it and respect that I'm telling you the truth judge, I just didn't know what to do but try to contact you directly."