A Florida man stabbed his wife to death before slashing his own throat in front of their three children in an apparent murder-suicide Monday night over an argument about disciplining one of the kids, authorities said.

Deputies responded to a home in Deltona around 6:15 p.m. after a 10-year-old boy ran to a neighbor’s house for help, yelling that his stepdad stabbed his mother during a fight, the Volusia County Sheriff's Office said Tuesday.

Deputies found the boy’s mother, identified as 26-year-old Byanca Cruz, dead at the scene. The boy’s stepdad, 31-year-old Oscar Salazar, was found in grave condition with slice wounds to his neck. Salazar later died at a hospital. 

"This is really, really a heartbreaking story," Volusia County Sheriff Mike Chitwood said during a press conference. "It is sickening on one end, again when you look you have three little kids involved here, a 10-year-old, a 5-year-old and a 2-year-old, who don't have their mother anymore."

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Oscar Salazar and Byanca Cruz

Oscar Salazar, 31, stabbed his wife, 26-year-old Byanca Cruz, to death Monday night before slashing his own throat in front of their three children, authorities said. (Volusia County Sheriff's Office)

None of the three children were harmed during the incident. Salazar was the biological father of the two younger children, the sheriff said.

Investigators determined the couple was having a fight over how Salazar disciplined the 5-year-old child when he began stabbing Cruz with a knife multiple times, the sheriff said.

bloody knife found at home

Investigators said the alleged murder weapon was a knife, which was found at the scene. (Volusia County Sheriff's Office)

Cruz was "loaded with defensive wounds," according to Chitwood, who described the incident as "a fight for her life."

Chitwood said that Salazar had been using the identity of an uninvolved man who had his truck stolen in Texas several years ago after somehow arriving in the U.S. from Mexico. Salazar's immigration status was unclear.

Sheriff Mike Chitwood speaking to reporters

Volusia County Sheriff Mike Chitwood told reporters that Cruz was "loaded with defensive wounds" and that it was "a fight for her life." (Volusia County Sheriff's Office)

Salazar was previously arrested in Orlando in 2016 for domestic abuse and was charged with battery against a pregnant woman. The sheriff’s office said the pregnant woman was identified as Cruz.

The 10-year-old boy was in the custody of his father while the other children were with their maternal grandmother.

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"The children will need a lot of love and support as they deal with this tragedy today and for the rest of their lives," the sheriff wrote on Twitter. I am just so sorry for their pain."