Christopher Miller, of Deer Park, pleads 'not guilty by insanity' in fatal shooting of his father, Suffolk Det. John Miller

A Deer Park man charged in the death of his father, a retired Suffolk police detective and longtime member of the Wyandanch Volunteer Fire Company, shot the victim four times on Wednesday morning before fleeing the scene, a Suffolk County prosecutor said on Thursday.

Christopher Miller, 43, charged with second-degree murder in the death of his father, John Miller, pleaded "not guilty by insanity" on Thursday during an arraignment in Central Islip. Suffolk police said Miller fatally shot his 75-year-old father at about 7 a.m. on Wednesday following an argument at their Bruno Lane home.

Assistant District Attorney Eric Aboulafia told Suffolk District Judge Eric Sachs that Miller confessed during a videotaped interview with police to killing his father, a beloved detective and firefighter. Sachs ordered Miller held without bail and scheduled the next hearing in the case for Monday.

According to court papers, Miller told police he fired a shotgun at his father’s torso four times "before driving the pointed end of the weapon into his head to finish him off."

Miller, dressed in a white Tyvek suit, seemed uneasy during the arraignment and said he did not wish to be represented by his court-appointed attorney, Dan Russo. Miller told Sachs that he pleaded "not guilty by insanity" before the judge persuaded him to allow Russo to represent him at the arraignment, saying he could select another attorney as the murder case proceeds. Russo later entered a plea of not guilty on behalf of Miller.

Russo said he met Miller just minutes before the arraignment and did not have a chance to discuss the case with the defendant.

"He didn’t know who I was, which is understandable, because he had never met me," Russo said after Thursday’s arraignment. "He is obviously going through a hard time and is cautious about who he is talking to."

The events that led to the fatal shooting began on Monday, when Miller was involved in a car accident with a motorist in Stony Brook, police said. The defendant got into a fight with the other driver and was taken to Stony Brook University Hospital for treatment of his injuries.

John Miller, unaware of his son’s whereabouts, attempted to report the defendant missing the following day. A Suffolk police officer arrived at his home on Tuesday to complete a missing-person report and later informed the retired detective his son was in the emergency room.

The victim picked up Miller at the hospital on Tuesday evening and brought him to his Deer Park home, where he has been living while going through a divorce, police said.

Father and son quarreled early Wednesday before Miller opened fire with the shotgun. He then fled the Bruno Lane home. The gunshots were recorded on nearby surveillance video, which also captured Miller fleeing the scene.

Miller attempted to steal a truck and then hid in a shed in the yard of a home on Seaman Neck Road. A resident saw Miller in the shed and called 911.

The officer who responded to that 911 call had also responded to John Miller’s missing-person report a day earlier, Aboulafia said.

"He said your father is worried about you," Aboulafia added. "Let me take you home ... little did that officer realize that he would be walking into a murder scene."

When the officer arrived at the Bruno Lane home with Miller, he found the retired detective’s body in a pool of blood, with the shotgun nearby. Police also recovered an AR-15 at the home, Abuolafia said. Miller tried to leave the home, but the officer detained him.

If convicted, Miller faces a maximum sentence of 25 years to life in prison.