A New Jersey man admitted on Wednesday that he killed his 3-year-old son in 2015 to save his romantic relationship with his teenage girlfriend.

David Creato Jr., 24, of Haddon Township, pleaded guilty to aggravated manslaughter in the October 2015 death of Brendan Creato. A statement by the Office of the Camden County Prosecutor said that, under the plea agreement, Creato will be sentenced to 10 years in prison.

"Creato stated under oath that he recklessly caused his son's death under circumstances manifesting extreme indifference to the value of human life by depriving Brendan of oxygen on Oct. 13, 2015," prosecutors said in the statement.

Creato will be required to serve at least eight and a half years of his sentence before he becomes eligible for parole. He is scheduled to be sentenced on Sept. 29.

Creato called 911 the morning Brendan died to report the boy missing, the Camden Courier-Post reported. He claimed that he woke up to find his son gone from his apartment.

Investigators searching for the missing boy found his body about three hours later, partially submerged in a river eight blocks from his father's home, the Courier-Post reported. Prosecutors said at the time that there were no signs of forced entry in the home, and Brendan's autopsy was inconclusive as to his cause of death.

The cause of death was revised that December to "homicidal violence of undetermined etiology," the Courier-Post reported. Evidence at the scene, including Brendan's clean socks, indicated that he could not have walked to the muddy area in which he was found.

The pathologist who made that determination, while conducting a third autopsy of the boy's body, testified in court that he found pinprick hemorrhages in Brendan's eyes and what appeared to be a bite mark inside the boy's cheek, the newspaper reported. The findings led prosecutors to conclude that Brendan was smothered.

Creato was charged with murder and endangering the welfare of a child in January 2016, three months after Brendan was killed. It was at the time of his arrest that prosecutors unveiled the supposed motive for the boy’s death: that Creato, then 22, killed his son in a desperate bid to hold onto his relationship with his 17-year-old girlfriend.

Creato and Julia Stensky argued many times in the months before Brendan was killed, over jealousy, finances and especially over Brendan, the Courier-Post reported. More than 9,000 texts over a four-month period depicted a contentious relationship that included an argument the weekend before Brendan died because Stensky, who was visiting Creato from her out-of-town college, was not happy Creato had custody that weekend.

Creato shared joint custody of his son with the boy's mother, who he still frequently spoke to, a fact that angered Stensky, according to texts detailed by the Courier-Post. When Stensky was critical of Brendan's mother, who gave birth at 19, Creato addressed his feelings for his son.

“Let’s get one thing straight. I don’t consider my son a mistake,” Creato wrote.

In an exchange on Oct. 6, a week before Brendan died, Stensky made her own feelings about the boy clear.

"I don't want to spend my precious time near your kid or any kid," Stensky wrote, according to the Courier-Post.

“Why do you hate him so much?” Creato asked. “Why can’t we be a family?”

The lack of a definitive cause of death, along with an absence of physical evidence, made the case against Creato a circumstantial one. When Creato went to trial in May, the judge declared a mistrial after jurors could not agree on a verdict.

The Courier-Post reported that 10 jurors favored a guilty verdict, while two did not.

Creato’s retrial was scheduled to begin Sept. 11.