RIVERVIEW, Fla. — A 14-year-old Florida boy is accused of fatally shooting his mother on Saturday, authorities said.

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The shooting occurred at about 4 p.m. in the Summerfield subdivision in the Tampa suburb of Riverview, WFLA-TV reported.

The teen also shot his mother’s boyfriend several times, Hillsborough County Sheriff Chad Chronister said during a news conference.

“When I tell you this is one of nightmares, one of heartbreak, the suspect is only 14 years of age,” the sheriff said. “This is family violence at its worst.”

The older brother of the teen said he heard an argument between his mother and her boyfriend, and then gunfire noises were heard in the residence, WTSP-TV reported. When the sibling investigated, he realized that his mother and her boyfriend had been shot, Chronister told reporters during a news conference.

The 14-year-old then turned his gun on his older brother, who fled the home, WFLA reported.

Deputies encountered the woman lying in the driveway. She was pronounced dead at the scene, Chronister told reporters.

“What we believe occurred is after he shot and killed his mom, he had already shot the boyfriend,” Chronister said. “He was running through the neighborhood in pursuit to try to finish the job.”

“This family’s lives have been changed forever,” Chronister said. “They lost a mother, this mother’s life is over,

Chronister said that the teen’s life “is over, too.” He had no criminal history.

“He will never see the outside of a detention facility,” the sheriff said.

It is unclear what the suspect’s mother and her boyfriend were allegedly arguing about. The older sibling was not injured, Chronister told reporters.

An investigation is ongoing, and the sheriff said a search warrant had been issued to enter the residence.