A Florida mother killed her own mother and two of her children before taking her own life in a murder-suicide, with police revealing that disputes over pornography on her husband's phone occurred in the days prior to the killings.

Hailey Dempsey, 27, fatally shot her mother, Valerie DeBoe, in the early morning hours of May 3 at her home in Plant City, located in the Tampa Bay area. Dempsey then fled the residence on foot with her three young daughters. She subsequently killed the four-year-old and four-month-old, and shot at her two-year-old, but missed. She then died by suicide.

Plant City Police Chief Richard Mills stated on Thursday that officers had been called to the Dempsey residence three times in the two days preceding the shootings. The initial call on Friday, May 1, was in response to a verbal argument concerning pornography that Dempsey had reportedly found on her husband Jay's cell phone.

"It wasn’t cheating or anything like that, evidently it was just porn, and they were having an argument over that," Mills told reporters. "I think that’s what everything stemmed from."

Later on the same day, police received another call because Dempsey suspected a tracking device might be on her car, but none was found. Dempsey left the property with her children and her 55-year-old mother, who was visiting from Clearwater, and they stayed at a hotel overnight.

The following day, police were called again to accompany the family back to their home to retrieve clothing, according to Chief Mills.

Dempsey's husband was detained following the murders. However, after a thorough investigation into his potential involvement, he was cleared as a suspect and was not arrested or charged. Mills indicated that there were "indications of some mental illness involved with the case."

"I’ve been in law enforcement for 34 years, I was on that scene, and it was probably the worst scene that I’ve ever seen in my life," Mills said, visibly emotional. "It’s absolutely heartbreaking. the worst thing I’ve ever seen in my life."

The surviving child is reported to be in good health and is staying with family members.