After attending a music festival with her boyfriend in October 2017, Cayley Mandadi died from injuries she sustained that day -- but what exactly caused her death?
Cayley Mandadi, 19, was a typical Texas teenager navigating life through school, sports and boys. Friends say Cayley had a good heart and was "full of love." Her mother says Cayley was a happy person who was trusting, warm and always smiling.
Cayley Mandadi was a sophomore studying communications at Trinity University, a small liberal arts college in San Antonio, Texas. In the fall of 2017, friends say Cayley finally felt like she was fitting in at school. She joined a sorority and was a member of the Trinity cheerleading team.
Cayley Mandadi dated Trinity student and football player Jett Birchum her freshman year. But the relationship was on again, off again ...
A New Man
There was another man in Cayley Mandadi's life – 22-year-old Mark Howerton. Growing up, Howerton had been a star high school baseball player. Mark was not a student at Trinity, but often visited his friends on campus. That's how he met Cayley. By October of 2017 their friendship turned into a romantic relationship.
A Rocky Relationship
Mark Howerton and Cayley Mandadi's relationship quickly turned rocky. According to campus police, a few weeks before her death, Howerton tore apart Cayley's dorm room. 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 Mark was banned from campus.
A Weekend of Partying
The last weekend of October 2017, Cayley Mandadi and Mark Howerton attended the Mala Luna Music Festival in San Antonio. The couple partied heavily, drinking and taking MDMA, a drug known as Molly or ecstasy. This photo was taken at the music festival.
According to Mark Howerton, on Sunday, October 29, 2017, the couple left Mala Luna sometime between 5 and 6 p.m. They got in an argument after seeing Cayley's ex-boyfriend, Jett Birchum, at the festival.
Howerton said they continued to argue in the car, but eventually stopped at a gas station to have "rough" make-up sex. Howerton would later tell police that shortly after sex, Cayley stopped breathing. That's when he rushed her to the nearest emergency room.
A Disturbing Scene
When Mark Howerton arrived at the emergency room, Cayley Mandadi was in the passenger seat of his car, unconscious. A paramedic testified that she saw "multiple bruises" on Cayley's legs, and immediately started CPR.
While doctors tried to save Cayley Mandadi's life, officers on the scene interviewed Mark Howerton about what happened that night. They took photos of his hands, as seen in this photo. Later, Cayley was taken off life support and declared deceased.
Mark Howerton Arrested
Three months after Cayley Mandadi's death, her autopsy report was released. It showed that she died from blunt force face and head trauma, and labeled as a homicide. Several weeks later, Mark Howerton was arrested and charged with murder and sexual assault. He pleaded not guilty and was released on bail.
In December 2019, Mark Howerton went on trial in San Antonio. John Hunter, Howerton's defense attorney, told "48 Hours," "This is a case where, there's more than meets the eye and things aren't what they seem."
Cayley's ex takes the stand
During trial, Cayley's ex-boyfriend, Jett Birchum, told the jury what he witnessed at the Mala Luna Music Festival. He testified that he saw Mark Howerton and Cayley Mandadi "having an intense conversation" and Cayley "trying to create space" and "get away." He said he then witnessed Howerton, "reach out his right arm and hook it around her shoulder and pull her in closer. And then turn and walk away."
Grilled on Cross Examination
During cross-examination, John Hunter grills Jett Birchum about what he says he saw that day. Birchum originally told police that he saw Mark Howerton pick Cayley Mandadi up and put her in his car as they were leaving the festival. On the stand, Birchum admits to lying about this to the grand jury, saying he didn't actually see Mark put Cayley in his car.
The Defense Theory
The defense presents a different theory of how Cayley Mandadi sustained her injuries that day. They say that while medical professionals desperately tried to revive Cayley seven times, they broke one of her ribs and badly bruised her body in the process. They argue Cayley's bruises were at the hands of the medical staff and not Mark Howerton.
A Fatal Fall?
Pharmacologist Jason Wallach testifies about the drug in Cayley Mandadi's system, saying it could have led to her death. He says high blood pressure from MDMA, the drug Cayley and Mark Howerton took the day of the festival, can increase the chance of a hemorrhage. He says it's possible that if Cayley fell and hit her head, it could have been fatal due to the MDMA.
After seven days of testimony, Mark Howerton's fate was in the hands of the jury. But just hours after the jury began deliberations, John Hunter unexpectedly learned of a new witness who contradicted what the EMT testified to earlier in the trial.
The witness told Hunter that she was working at the front desk of the hospital the night Cayley Mandadi was brought in and saw no bruises on her legs.
However, the judge said it was too late to call the new witness.
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. The prosecution plans to re-try the case. Cayley Mandadi's mother, Alison Steele [pictured] says she won't give up in her fight for justice for Cayley.
Alison Steele has turned her grief into action. In September 2019, she was able to get the CLEAR Alert Bill passed. Now in the state of Texas when someone between the ages of 18-64 goes missing, an emergency text will go out to the community. Steele wants "Cayley's story to be used to help other people."
Taylor Clement will never forget her best friend. She told "48 Hours" that she had always planned to have Cayley as her maid of honor in her wedding someday, and the godmother to her future children. She said this photo of them "smiling at prom is [her] absolute favorite."