Father Expected To Plead Guilty To Murdering South Pasadena Boy, 5

SOUTH PASADENA, CA — The father suspected of murdering his 5-year-old son, triggering a desperate months-long search for the little boy from South Pasadena, will plead guilty to murder Tuesday, according to ABC Eyewitness News.

Citing unnamed sources ABC reports that Aramazd Andressian Sr. is expected to face a sentence of 25 years to life in prison.

Andressian , was arrested in June in Las Vegas after he changed his appearance and appeared to be preparing to flee the country, according to investigators. Police believe he killed his son to get back at his estranged wife amid a bitter divorce.

His little boy was last seen at 1 a.m. April 21 leaving Disneyland with his father, who was found unconscious at Arroyo Seco Park in South Pasadena the next day and was unable to account for his son's whereabouts.

Los Angeles County sheriff's homicide Lt. Joe Mendoza alleged the killing was "pre-planned" and took place between the time Andressian and his son left Disneyland and the father was discovered unconscious at the South Pasadena park.

RELATED: Father Suspected Of Murdering Son Is 'Victim Of Rush To Judgement,' Attorney Says

Andressian told investigators he arrived at the park with his son and waited for the golf course to open, and admitted ingesting prescription medication that was not prescribed to him, Mendoza said. Andressian has been uncooperative and gave false information to investigators since he fell under suspicion, Mendoza said.

The father said he did not remember what happened to his child or any details that were useful in locating the boy, according to Mendoza, who said a prescription bottle was found inside Andressian's car, which was doused with gasoline inside and out.

Mendoza alleged that Andressian planned his son's murder to get back at his estranged wife during a "tumultuous" divorce and then tried to commit suicide -- before heading to Las Vegas to prepare to flee the country.

The investigation into the boy's disappearance included several weeks of surveillance, during which the suspect "significantly" changed his appearance, acted in a manner inconsistent with the behavior of a grieving parent and appeared to be planning to flee to a country from which he could not be extradited, Mendoza said.

Sheriff's officials have not provided specifics on any new evidence explaining the suspect's latest arrest. He was originally arrested in Los Angeles County shortly after his son went missing, but was later released for lack of evidence.

At an extradition hearing in Las Vegas Andressian, sporting dyed, light-colored hair, calmly told a judge that he would not resist being sent back to Los Angeles.

"If California wants me they can come get me ... ," he said.

The remains of Aramazd Andressian Jr. were discovered last month near the Lake Cachuma Recreation Area in Santa Barbara County, according to the Los Angeles County Sheriff's Department. The search for the boy had spanned several Southern California counties.

City News Service contributed to this report; Photo: Aramazd Andressian Sr. appears in court Tuesday, June 27, 2017, in Las Vegas. Andressian Sr. was arrested Friday in Las Vegas and is being held on $10 million bail. Authorities in Los Angeles say they believe Andressian killed his missing 5-year-old son to get back at his estranged wife during a bitter separation. (AP Photo/John Locher)