Aramazd Andressian was in a bitter custody dispute with the mother of their 5-year-old son, investigators said.
The California father charged with killing his 5-year-old son during a particularly bitter custody dispute has pleaded guilty to murdering him.
Aramazd Andressian Sr., 35, will be sentenced to 25 years to life in prison when he returns to court on Aug. 23, authorities said.
Read: Body of Missing Boy, 5, Turns Up Near Lake Months After Father Was Found Passed Out in Car
The child's family wept in court Tuesday as the prosecutor said the boy's name and read the charges against his father.
The dad had been charged in June with murdering his son, who had been missing for two months.
Aramazd Andressian Jr. was the subject of brutal custody fight and was killed by his father to get back at his estranged wife, investigators said.
The 35-year-old Los Angeles County man had been picked up in Las Vegas, where he was partying, authorities said.
“The time was right to make the arrest. Aramazd Andressian was being a flight risk,” Sheriff Jim McDonnell said after his arrest.
Andressian was preparing to leave the country and had altered his appearance by shaving his beard and lightening his hair, authorities said.
He was extradited to Los Angeles, McDonnell said.
The father and son were last seen together at about 1 a.m. on April 21, as they were leaving Disneyland, where they had been spending the day with relatives.
The child was reported missing on April 22 by his mother after her ex-husband failed to return the boy at a scheduled custody transfer, authorities said.
Read: Father Charged With Murdering 5-Year-Old Son Who Was Reported Missing
Andressian Sr. was found later that morning, unconscious in a South Pasadena park. The boy was nowhere to be found. The father told officers someone must have taken the child while he was passed out.
The father told investigators he had taken his son to the park while they waited for a nearby golf course to open. Andressian Sr. said he may have been attacked. He did not remember losing consciousness, he told authorities.
He was arrested that same day, but later released due to insufficient evidence, detectives said.
After his second arrest, he ultimately told investigators where to find the boy’s body, which he had buried in Santa Barbara County, authorities said. The child's cause of death has not been released.
Watch: Mom Pleads for Return of 5-Year-Old Who Disappeared Last Month
