An unemployed New York man from a prestigious military family told authorities that he put his mother in a headlock and drowned her in their pool after she berated him for not taking his medicine.

23-year-old Denis Cullen Jr. is said to have shown no remorse during his video confession concerning the murder of 63-year-old Elizabeth Cullen.

Instead, he sat in wonder at how much his mother struggled in and out of the water as he’d thrown his arm around her neck, dragged her to the pool, pulled her into the deep end, then held her underwater til she died.

Assistant District Attorney Robert Biancavilla said during a brief court appearance in Suffolk County court Thursday, “This is a son who killed his mother, and the way he killed her, the way he describes how it was done, is chilling.”

He and his mother were arguing Wednesday morning in their home about his refusal to take his meds. It wasn’t clear what the medication was treating.

During the argument, she poked him and this set him off.

“After she poked him, he put her in a headlock, waled her from the shallow end of the pool to the deep end of the pool, all the while she struggled,” Biancavilla said. “He said she struggled violently and he was surprised a woman of her stature could struggle as much as she did.”

The victim was just 5’2.

After his mother stopped struggling during the violent incident,he pulled his mother’s lifeless body out of the pool, then dragged it over next to a shed and covered her body with a dinghy.

He then calmly went inside the $1.8 million house and took a shower before taking some money from his mother’s wallet, they keys to her car, and a credit card.

He’s said to have then driven to a nearby train station, hopped a train, and headed into the city to meet his sister.

While on the commute, he called that sister, who in turn called their father, Denis Cullen. He called the cops.

The call came in at around 3:45 p.m. Wednesday “about a possible intentional drowning,” leading cops to enter the neighborhood filled with multi-million dollar homes.

Lloyd Harbor police Suffolk County Police, which intervenes in homicide cases, then found the deceased mother’s body in the backyard.

Mr. Cullen returned to the scene of the grisly crime with his father and sister, and was taken into custody without incident.

He was charged with murder in the second degree and is being held on $8 million bail.

He pleaded not guilty to the charge and is next due in court on August 23rd.

He had no a criminal history before the murder of his mother.