New York Kayak Murder Case: Interrogation Video Reveals More Details About Victim’s Mysterious Death

— -- Never-before-seen interrogation video of Angelika Graswald, the woman accused of killing her fiancé Vincent Viafore while kayaking in New York’s Hudson River, reveals more details about the mysterious circumstances surrounding his death.

Graswald, 35, says she and Viafore, 46, had been out kayaking on the Hudson River on April 19. She said his kayak flipped over and she wasn’t able to reach him before he disappeared beneath the surface.

Prosecutors claim Graswald admitted to tampering with Viafore’s paddle and the drain plug on his kayak, which they allege she did on purpose to make him drown. Graswald is now facing second-degree murder and second-degree manslaughter charges related to his death. She has pleaded not guilty to all charges.

After her arrest in April, New York State Police questioned Graswald, a Latvian native, for nearly 12 hours, which her defense attorney Richard Portale said was a “grueling” experience for her, especially since she still struggles with the English language. In video footage from the interrogation obtained by ABC News, Graswald was seen cooped up overnight, stretching in various yoga poses.

During the interrogation, Graswald told investigators that she had removed the drain plug from Viafore’s kayak days before they went out, and didn’t realize she hadn’t put it back until they were already out on the Hudson. When asked why she hadn’t brought the plug with her, she said, “I thought he had it,” and then later she said, “He didn't have it because I guess I had it.”

“We were already in the water. I’m like, ‘Yo, where’s your plug. Are you kidding me? I was mad at him,” she told investigators. “His boat starting to get lower in the water… because of the waves, because of the plug not being in there… [The kayak] started to fill up, and I knew that the plug wasn’t in there. I was like ‘oh this is not good.’”

Viafore wasn’t wearing a life jacket or a protective dry suit, and had been drinking that day, which was confirmed by the toxicology report obtained by ABC News. Graswald told investigators that she tried to get closer to Viafore to help him, but the water was too rough.

She then told investigators that she watched him struggle as she called 911. In a tape of the 911 call obtained by ABC News, Graswald is heard telling the 911 operator that she couldn’t reach Viafore and to please send help.

“He has something that he's holding onto, but it's getting very bad. The waves are very strong, I can still see his head,” Graswald said during the 15-minute call.

Then, before the call ends, Graswald told the operator, “I think he drowned, I need him to be rescued.”

Police noted in their reports that water temperatures at the time of the incident were around 40 degrees and Graswald was treated for hypothermia at a local hospital and released.

“The only thing that she could’ve done, would’ve been to have him hold onto her boat, and bulldoze him to shore,” said expert kayaker Carl Ladd, who is an American Canoe Association level-five instructor. “But with water temperatures that cold, he might not have made it... She was lucky to survive as well.”