The New York woman charged with killing her fiance by sabotaging his kayak during a ride on the Hudson River told a detective she wanted him dead, according to footage of the interrogation.

"I wanted him dead," Angelika Graswald tells a state police investigator during an interview in the footage obtained by CBS' "48 Hours." ''And now he's gone."

Graswald has pleaded not guilty to murder and manslaughter charges. Her attorney, Richard Portale, didn't immediately return a call seeking comment Saturday. He has said his client's statements to police were coerced.

Graswald, 35, killed her husband-to-be, Vincent Viafore, by removing a drain plug from the kayak and pushing a floating paddle away from him after he capsized on April 19, prosecutors have argued. They say she was motivated by a $250,000 life insurance policy and felt trapped in the relationship. She's being held on $3 million bail.

But Portale has disputed that theory, arguing Viafore, 45, died accidentally after having had a few beers and falling into the cold water. His body was discovered in May.

The drowning death was ruled a homicide by a medical examiner who wrote in an autopsy report obtained by The New York Times that Viafore's death was the result of a "kayak drain plug intentionally removed by other."

Portale told the newspaper the medical examiner's ruling was ill-informed and lacked medical evidence.