The young man charged with killing his mother in the family pool has reportedly confessed to the crime. A Suffolk County assistant district attorney said, "The way he killed her, the way he describes how it was done, is chilling."

On Wednesday afternoon, Suffolk police were called to the Cold Spring Harbor home of Sean and Elizabeth Cullen to check on Elizabeth Cullen's well-being. They discovered the 63-year-old's body, and while they were at the house, son Denis Dyson Cullen returned and the police took him into custody.

Suffolk County ADA Robert Biancavilla said that the mother and son had been arguing about Denis taking his medication, "The argument escalated to the point where she had poked him. After she poked him, he put her in a headlock, walked her from the shallow end of the pool to the deep end of the pool, all the while she struggled. He said she struggled violently and he was surprised a woman of her stature could struggle as much as she did."

Newsday reports, "Denis Cullen then carried her body out of the pool and placed it next to a shed in the backyard and covered her body with a dinghy... Denis Cullen then went into the home where he lived with his mother, father and one of his three sisters, and took a shower, Biancavilla said. He then took money from his mother’s wallet, a credit card and her car keys and drove to the nearby Long Island Rail Road station in Cold Spring Harbor and took the train into the city."

In NYC, Cullen allegedly met with his sister and confessed, prompting her to call their father, who then contacted the police to check on his wife. Cullen went back to the home with his father and sister and was arrested there.

The 23-year-old is being held on $5 million bail/$8 million bond. Cullen's defense attorney said, "There's a lot of work to be done. I have to determine if he had a psychiatric background. I have to determine if he's under a doctor's care. And I have to look at a videotape," adding, "He hasn’t been convicted of anything, so he's not sorry at this point; he hasn’t said 'I'm sorry.'"