Police say digital evidence pointed to possible mental illness as investigators reconstructed the timeline and ruled out the surviving child’s father as a suspect
Three months ago, the Plant City community was shaken by a quadruple homicide investigation that left a grandmother, mother and two children dead. Today, the Plant City Police Department has ruled the investigation a murder-suicide.
Mother of three, Haley Dempsey, murdered her own mother before taking the lives of her 4-year-old and 4-month-old daughters and then killing herself. She attempted to kill her 2-year-old daughter, who survived and remained at the scene for almost an hour before police arrived.
“When we found them, there was no identification, no driver license, no phones, it was just the gun. So, she left the house with the gun and the girls and that was it. This played into account on why it took us so long to identify her and then backtrack to the house,” said Plant City Police Chief Richard Mills.
On May 3, Mills said surveillance and Ring camera footage showed Dempsey leaving the residence at 5:35 a.m. with her three children after shooting her mother.
She traveled eastbound through the neighborhood along West Saunders Street and West Tever Street.
Investigators were able to track her movements through multiple security cameras and Ring doorbell recordings. The videos showed her walking through the neighborhood with her three children and, at one point, approaching a residence and asking someone inside for help.
According to police, the resident went to get her husband, but when they returned, Dempsey and the children had left. Ring camera footage showed two of the children crying during the encounter.
Investigators ultimately tracked Dempsey and the children from 5:35 a.m. until approximately 6:01 a.m.
Around 6:40 a.m., a witness reported seeing Dempsey walking along the roadway.
At approximately 6:57 a.m., police determined Dempsey shot and killed her 4-year-old and 4-month-old daughters behind bushes in the front yard of a residence on West Tever Street.
She then attempted to shoot her 2-year-old daughter but missed before turning the firearm on herself.
Police arrived approximately 50 minutes later and found the surviving 2-year-old at the scene.
The firearm recovered at the scene was sent to the Bureau of Alcohol, Tobacco, Firearms and Explosives for testing, police said.
There is no confirmed motive for the killings, but Mills said investigators found indications of possible mental illness through digital evidence.
Later that afternoon, police detained Haley Dempsey’s husband, Jay Dempsey, when he returned to the residence from a friend’s house in Lakeland. Dempsey was never arrested or charged in connection with the investigation.
However, investigators had to rule him out as a suspect. After interviews and reviewing Jay Dempsey’s cellphone data, detectives determined he was on Interstate 4 traveling back to Plant City at the time Haley committed the murder-suicide.
“An investigation of this magnitude takes time, and I understand how upsetting and unnerving this tragedy has been for this tight knit community,” Mills said. “From the very beginning our detectives were committed to getting answers for both the families and our community. At the onset and throughout the investigation, the evidence available to us did not indicate that there was an ongoing threat to our community.”
Mills said police could not release information during the investigation because the department did not want to jeopardize witness statements, contaminate evidence or compromise investigative strategies.
Police had responded to the Dempsey residence on May 1 and May 2, two days before the killings.
On May 1, officers responded to the home after a verbal argument between Haley and Jay Dempsey. Mills said there was no indication of violence or criminal activity.
Haley’s mother was staying at the home at the time, and police said the argument involved pornography found on one of Jay’s phones.
Officers remained at the home while Haley, her mother and the three children gathered their belongings and left to stay at a hotel.
Later that day, Haley contacted police because she believed a tracking device had been placed on her vehicle. Officers searched the vehicle but did not find one.
On May 2, police returned to the residence to assist Haley, her mother and the children while they retrieved additional clothing. Jay Dempsey was not at the residence and was staying with a friend in Lakeland.
Police said there was no indication of physical violence during either response.
