PLANT CITY — A Hillsborough County sheriff's deputy killed his wife, daughter and granddaughter early Wednesday morning, then confessed to their murders over his agency radio before killing himself.

Terry L. Strawn, 58, a Sheriff's Office veteran who was once named Officer of the Year, used his service handgun to kill his family at two locations in east Hillsborough County. Three deputies encountered him near Plant City High School and tried to talk him down before he died by suicide.

"He indicated he was losing everything," said Hillsborough Sheriff Chad Chronister. "I'm saddened. But I'm also disheartened that a sheriff's deputy would ever cause harm to another individual."

FROM SEPTEMBER: Deputy's wife texted 'Kirk has lost his mind' before murder-suicide, friend says

The victims were identified as the deputy's wife, Theresa Strawn, 54; daughter, Courtney, 32; and his 6-year-old granddaughter, Londyn, who was Courtney Strawn's daughter. The youngest casualty was a student at Valrico Elementary School, where Strawn worked as a school resource officer.

Sheriff's officials learned of the carnage at 6:42 a.m., when Strawn started speaking over a sheriff's radio frequency. He announced he had "emergency traffic," then said he had killed three family members and gave directions to the two locations where they could be found, the sheriff said. The deputy said he planned to kill himself at Plant City High, which is near one of the murder scenes.

A communications supervisor tried to talk him out of it. A short time later, deputies found Strawn just east of the school. They pleaded with him not to hurt himself.

"At one point he said he had to go, he wanted to be with his family," Chronister said.

No students or school staff were in the area, officials said, when the deputy killed himself.

Detectives and forensic technicians combed through three crime scenes Wednesday afternoon: An area just outside the Plant City High campus, Courtney Strawn's duplex near the school and the deputy's home in a gated community at 1512 Emerald Hill Way in Valrico.

"During his radio transmission, he talked about how much he loved the Sheriff's Office," Chronister said.

Terry Strawn also spoke of coping with financial and health problems, the sheriff said, but no financial concerns surfaced during his recent pre-employment background check when the retired deputy returned to duty this past summer.

In 2011, the deputy and his wife filed for bankruptcy protection in federal court. In a petition, they estimated their assets at less than $50,000 with liabilities greater than that. Among the assets, they listed a Jeep, two trucks, a boat, and a 9mm Smith & Wesson firearm. But court records show they qualified for a mortgage and bought a house earlier this year.

Strawn started with the Sheriff's Office in 1991. State law enforcement records indicate he began as a jail deputy before joining road patrol in 1995.

In 2004, he and another deputy shot and killed a man while responding to a domestic violence call. The man pointed a metal and plastic tool at the deputies as they tried to arrest him, according to news accounts of the incident. Fearing the object was a gun, the deputies fired their weapons.

Strawn was named an Officer of the Year in 2009. Sheriff's officials cited his work in removing dangerous criminals from the streets.

"Deputy Strawn is persistent, leaving no stone unturned in his pursuit of the lawbreakers," then-Sheriff David Gee said. "Recently he arrested a fugitive and an armed robbery suspect after a traffic stop. His high rate of success in the location and capture of numerous suspects has earned him this year's top honor in east Hillsborough County."

Strawn retired about two years ago, Chronister said. But he was re-hired over the summer as part of a sheriff's partnership with the Hillsborough County School District to improve security in local elementary schools.

The program was created in response to a new law passed after February's mass shooting at Marjory Stoneman Douglas High School in Parkland. The Sheriff's Office pledged to recruit and train more than 100 officers for elementary schools, providing 132 hours of comprehensive firearms safety and proficiency training.

Things were going so well in Strawn's new assignment that the agency recently decided to hire him back permanently, Chronister said.

As they lined up after school Wednesday to take their children home, parents at Valrico Elementary — where Strawn worked and his granddaughter attended school — started to hear about what had happened. As she sat in her car waiting for her son, Ingrid Martinez said she'd heard only about "a tragedy" but no details.

Shown a photo of Strawn, Martinez said her son, a second grader, used to call the same man "the nice policeman."

"He would sit down with them sometimes at lunch," Martinez said. "My son would always say, 'He's a very nice guy, Mommy.'"

The school district said crisis team members would be available to students and staff at Valrico Elementary.

"Londyn was a first grade student at the school. She loved to learn and was excited about reading and math. She had a kind spirit and always helped classmates," district spokeswoman Tanya Arja said in a statement about the 6-year-old victim.

The sheriff said Strawn underwent "extensive" background and psychological testing before he was re-hired.

"He had a phenomenal reputation throughout the Sheriff's Office," Chronister said. "No indication whatsoever … that this deputy would conduct himself in the manner he did."

The slayings mark the second time this year that a Hillsborough deputy was blamed for a domestic violence-related murder-suicide. In September, Deputy Kirk Keithley shot his wife, Samantha, in their Land O' Lakes home, then killed himself.

"We've been concerned because we've seen suicide rates have risen," Chronister said. "Why is this occurring? I wish I knew."

Times staff writers Howard Altman, Anastasia Dawson and Marlene Sokol, and senior news researcher John Martin contributed to this report.