DAYTONA BEACH, Fla. -- David Mohney wanted big changes for his family: to end his turbulent marriage, move his children 1,900 miles from Florida to South Dakota and transition from being a stay-at-home dad to starting work as a chiropractor.

Instead, authorities say, 52-year-old Mohney reached for a gun after arguing with his wife and shot all three of their children before killing himself. The couple's youngest, a 9-year-old daughter, survived. But both of her siblings died along with their father.

"If he wants to commit suicide, let him commit suicide. To shoot the children, that's cowardly," Volusia County Sheriff Ben Johnson said the outside the family's home hours after the slayings occurred before dawn Friday.

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The family had lived in Florida for about four years, and the volatile relationship David Mohney had with his wife, Cynthia, seemed to be no secret in their middle-class neighborhood just south of Daytona Beach.

"You can't believe either one of them," a neighbor told a 911 dispatcher after Cynthia Mohney came to his home screaming at 5:11 a.m. Friday. The man, whose name and address were redacted from the 911 recording provided by authorities, also said neither parent should have had children because they were "a little bit selfish and self-centered." The distraught wife can be heard in the background of the recording crying hysterically, repeatedly saying "Oh my god!"

At the Mohneys' home, deputies found 14-year-old Savannah Mohney and 9-year-old Lauren Mohney both shot in an upstairs bedroom. Their 11-year-old brother, also named David, was in a bedroom on the ground floor. Their father was in the kitchen with a handgun next to him.

Lauren was taken to a hospital and was later reported to be in stable condition.

The slayings occurred as David and Cynthia Mohney were entrenched in a bitter divorce after nearly 25 years of marriage. Court filings showed David Mohney wanted to leave his wife and move with their children to South Dakota. He had recently finished chiropractic school while she supported the family working as a physician's assistant, making $220,000.

Nearly a month after he filed for divorce, the husband sought a protective injunction against his wife June 3. He said in court papers his wife had been drinking heavily and slapping him and their children on their chests, backs and arms. Florida's child welfare agency said Cynthia Mohney had recently been treated for substance abuse.

In his divorce filing, David Mohney said his family moved to Florida in 2010 so he could study at Palmer College of Chiropractic's campus in Port Orange. He graduated in September 2013, but failed his first time taking the board exam and hoped to try again soon. He said in the court papers that returning to Rapid City, South Dakota, had been his family's plan all along, but his wife had become opposed to it.

He said his children also wanted to make the 1,900-mile move to get relief from their allergies and because they found the Midwest region better suited their "morals and values." David Mohney said he and his children also "prefer living in a climate with snow to celebrate Christmas and other holidays."

When he filed for divorce, David Mohney said little about problems with his wife. He made more specific accusations when he asked a Volusia County court for a protective injunction June 3.

In that filing, David Mohney cited four instances between April 4 and May 29 in which he said his wife had slapped one or more of their children. He said his wife would hit the children - sometimes several times - for arguing with each other, talking back to her, or for not picking up their toys and clothes when she told them to.

"The 'hits' described in the examples are loud and hard, beyond corporal punishment," David Mohney wrote. "My children were crying, afraid and trying to duck or get away from Cynthia."

However, he dismissed the request for protection two weeks after filing it.

The state's child abuse hotline was notified in June that Cynthia Mohney had a substance abuse problem after an incident at a restaurant. Cynthia Mohney followed through on treatment, according to the Department of Children and Families.