Tanner Horner wrote a letter from jail to murder victim Athena Strand’s family.Wise Co. Sheriff’s Office

A letter penned by admitted killer Tanner Horner to the grieving family of his young victim, Athena Strand, was chillingly read aloud in court during his sentencing trial, RadarOnline.com can reveal.

The former FedEx driver wrote the note to the 7-year-old’s family shortly before a 2023 suicide attempt behind bars, following the November 2022 murder of the little girl, whom he had been delivering a Barbie doll to for Christmas.

Tanner Horner Wrote a Letter to Athena Strand’s Family Before Suicide Attempt

Tanner Horner left the letter laid out before attempting to take his own life inside his jail cell. WFAA/YouTube

Sgt. Brett Yaro told the court he discovered the disturbing letters spread out inside Horner’s Wise County jail cell after the accused killer was rushed to the hospital following his suicide attempt.

One note sat beside an envelope addressed “Athena’s Family,” while another was ominously marked “Detectives ONLY!!!”

“I’ve done a terrible thing to your family, and I’m sorry. I can’t tell you how many countless nights I’ve stayed awake, unable to sleep. I pray for all of you,” Horner began in the letter, which was read aloud by the prosecution to jurors.

“I pray for all of you. So many people were affected by my breakdown,” the note continued. “Not just your family but my own as well. You’ll never get to see your baby girl grow up, and I’m sorry. Now my son is going to grow up without his father and protector.”

Tanner Horner Wanted to Explain ‘Where His Mind Was at’ Before Murder

Tanner Horner wrote about his alleged mental breakdown that led to Athena Strand’s murder.Wise Co. Sheriff’s Office

Horner wrote that he owed it to Athena’s family “to explain where my mind was at.” He then began to describe what caused the series of events that led to the little girl’s horrific murder.

The ex-delivery driver explained that he was diagnosed with Asperger’s Syndrome and doesn’t cope “well with change or things that are unpredictable in nature.”

Horner claimed he spiraled into breakdowns and even suicidal thoughts when changes were made to his FedEx delivery route, saying he was eventually put on medication before returning to work — only to be assigned as a “floating driver,” with a constantly shifting route that he said fueled his distress.

Tanner Horner Claimed Athena Strand Was In the ‘Wrong Place at the Wrong Time’

Tanner Horner ended his letter by asking for ‘forgiveness.’WFAA/YouTube

“The holidays came & my stress only multiplied. They forced everyone to work 6 day weeks as volume got higher & higher,” Horner explained about the days leading up to Strand’s abduction and murder.

He claimed the child was in “the wrong place and wrong time” when he made the delivery of what was to be her Christmas present to her Paradise, Texas, home, telling her family, “I’m sorry I allowed my mental state to be unstable.”

“I’m sorry I took your little angel away from you. She didn’t deserve it. Y’all didn’t deserve it,” Horner shared, while asking for “forgiveness.”

He signed his letter, “With love & sorrow & remorse.”

Jury Deciding on Life in Prison or the Death Penalty for Tanner Horner

The scared little girl was seen being driven to her death by killer Tanner Horner, who couldn’t look at the tape. WFAA/YouTube

Horner pleaded guilty to capital murder and aggravated kidnapping on April 7, just as his trial was about to begin. Jurors are now hearing testimony on whether he should serve life in prison without the possibility of parole or get the death penalty.

The convict initially claimed he hit Strand with his truck and took her in a panic, but video from inside the vehicle showed the young girl conscious, confused and seemingly unharmed.

Horner later admitted to authorities that he tried to break Strand’s neck before ultimately strangling her with his bare hands, then dumping her body in the Trinity River.

Jurors have already been forced to listen to the harrowing audio of the murder, including the terrified child pleading for her mother.