Cayley Mandadi, 19, was a typical Texas teen navigating life with school, sports, and boys. Friends claim she had a big heart and was “full of love.” Her mother describes Cayley as a happy person who was trusting, warm, and always smiling.
Mandadi was a sophomore in communications at Trinity University, a small liberal arts college in San Antonio, Texas. Mandadi finally felt like she belonged at school in the fall of 2017, according to her friends. She joined a sorority and was a member of the Trinity cheerleading squad.
A new man in Mandadi’s life
Mandadi had another man in her life: Mark Howerton, who was 22 years old. Growing up, Howerton was a standout high school baseball player.
Howerton was not a Trinity student, but he frequently visited his friends on campus. This is how he met Mandadi. By October 2017, their friendship had developed into a romantic relationship.
A rocky relationship
After having an argument, Howerton reportedly threw her clothes in the trees, cracked a sliding glass door and later smashed her laptop. The Trinity University Police Department was called to the scene and Howerton was banned from campus.
A weekend of partying
Mandadi and Howerton attended the Mala Luna Music Festival in San Antonio over the last weekend in October 2017. The couple took MDMA, also known as Molly or Ecstasy. This photograph was taken at a music festival.
Tragedy strikes
According to Howerton, on Sunday, October 29, 2017, the couple left Mala Luna after 4 p.m. They had an argument after seeing Mandadi’s ex-boyfriend, Jett Birchum, at the festival.
According to Howerton, they argued in the car before stopping in a parking lot for “rough” make-up sex. Howerton later told police that Mandadi stopped breathing shortly after having sex. He eventually brought her to the ER.
A disturbing scene
Mark Howerton’s hands
While doctors attempted to save Mandadi’s life, officers on the scene questioned Mark Howerton about what had occurred that night. They took this photograph of his hands.
Mark Howerton arrested
The autopsy report for Mandadi was released three months after her death. It revealed that she died from blunt force trauma to the face and head, and her death was ruled a homicide. A few weeks later, Howerton was arrested and charged with murder and sexual assault. He pleaded not guilty and was released on bail.
Defending Mark Howerton
In December 2019, Howerton went on trial in San Antonio for the murder of Mandadi.
“This is a case where, there’s more than meets the eye and things aren’t what they seem,” John Hunter, Howerton’s defense attorney, told “48 Hours.”
Mandadi’s ex-boyfriend takes the stand
During the trial, Birchum told the jury what he saw at the Mala Luna Music festival. He stated that he witnessed Howerton and Mandadi “having an intense conversation” and Mandadi “trying to create space” and “get away.” He claimed he then saw Howerton “reach out his right arm, hook it around her shoulder, and pull her in closer.” “Then turn and walk away.”
During cross-examination, Hunter questioned Birchum about what he claims he saw that day. Birchum initially told police that he saw Howerton pick up Mandadi and place her in his car as they left the festival. Birchum admitted on the stand that he misled police by claiming that he did not see Howerton put Mandadi in his car.
The defense theory
The defense presents a different theory for Mandadi’s injuries that day. They argue that Mandadi’s bruises were caused by the medical staff, not Howerton. They claim the cause was the organ donation process, and when medical personnel attempted to revive Mandadi seven times, they broke one of her ribs and bruised her body.
A hung jury pushes Mandadi’s parents to start their own investigation
After 10 hours of deliberations over two days, the jury notified the judge that they were unable to come to a decision. A mistrial was declared.
While prosecutors planned to retry Howerton, Cayley’s mother Alison Steele (pictured) and stepfather Lawrence Baitland decided the jury needed more information about what happened inside Howerton’s car.
Mandadi’s parents develop their own theory
Steele and Baitland focused on an autopsy photo that showed a small dot-shaped bruise above Cayley’s right ear and a larger bruise above Cayley’s left ear.
Steele believes Cayley’s fatal injury occurred when Howerton “reached from his driver’s seat, hit her in the left ear, and drove her head into the window and onto the lock button of the car.”
Steele and Baitland visited a used car lot, where Steele posed in a Mercedes similar to the one Howerton drove on the night Cayley was killed.
This is one of several photographs Baitland took of Steele posing in the car. He stated that during “48 Hours” she “photographed her head in different positions while … holding the autopsy images, trying to see if they match up with the door and it’s a near perfect match.”
Mandadi’s stepfather develops a 3D model
Emboldened by the photos he took, Lawrence Baitland, a NASA engineer, constructed a 3D model of Mandadi’s head. He layered in photos of Cayley and the autopsy photo showing that dot above Cayley’s right ear.
“So this gave me the confidence to go to the next step, which was to seek out the killer’s car,” Baitland said.
Tracking down the alleged killer’s car and commissioning a reenactment video
Bailtland located Howerton’s Mercedes. He persuaded the owner to sell him the car.
Baitland and Steele then hired a private investigator to create a reenactment video of what they believe occurred in the car, featuring actors similar in size to Mandadi and Howerton. This is a still frame from that video.
Howerton found guilty of aggravated assault at his second trial
Howerton is seen in court at the beginning of his second trial in May 2023.
The prosecution chose not to present Steele and Baitland’s reenactment video as evidence, fearing that the defense’s cross-examination of it would undermine the case.
The jury found Howerton not guilty of murder, but of aggravated assault resulting in serious bodily injury. He was sentenced to a maximum of 20 years in prison. He is eligible for parole in May 2033.
Mandadi’s parents continue to fight for victims
Friends forever
Taylor Clement will not forget her best friend. She told “48 Hours” that she had always planned to have Mandadi as her maid of honor at her wedding and godmother to her future children. She stated that the photo of them “smiling at prom is [her] absolute favorite.”