He Vanished on a Montana Boat Trip. His Family Is Haunted by Questions.

Four weeks ago, a college basketball player, on a lake trip with his girlfriend and her family and friends in Montana, went over the side of the boat and vanished in 140-foot-deep water.

The disappearance and presumed drowning of Mamadou N’Diaye left his family of African immigrants in grief and confusion; his girlfriend, who is white, fending off demands for answers and accusations of racism; and police, who labeled the incident a tragic accident, searching for the body.

On Friday, at least one matter was resolved when authorities revealed that a private rescue organization searching Lake Koocanusa had pinpointed what looked like a body on sonar and hours later had recovered the 18-year-old’s remains.

But the family says there are still loose ends.

“Our questions remain unanswered,” said Mouhamed Diallo, a family representative who is on the board of a racial-justice organization named after his cousin, Amadou, the victim of a notorious 1999 NYPD shooting.

“There has to be an autopsy,” Diallo told The Daily Beast on Friday afternoon.

Capt. Boyd White of the Lincoln County Sheriff's Office said there is no question that it’s N’Diaye’s body, which is now being sent to a coroner in Libby, Montana. No decision on an autopsy had been made. 

“We are discussing our legal authority on it,” White said.

Born in Baltimore, N’Diaye was on his way to realizing his dreams for him when he vanished into the lake. His father, Mamour N’Diaye, who is from the West African nation of Guinea, told The Daily Beast in recent days that his son “was the hope of our family.”

On July 9, N’Diaye, a rising sophomore at Northern Vermont University, flew to Montana to visit his girlfriend, Cheyann Tooman, who is also a basketball player at the school and was home recovering from ankle surgery.

They took a planned trip to Lake Koocanusa, near the town of Eureka and the Canadian border, a meeting spot for much of her family. On Friday, July 24, out on a boat with nine other people, they dropped anchor after lunch with plans to swim, she said.

“I was like, ‘Well, he probably won’t do that because he can’t swim,’" Tooman told The Daily Beast. But, she said, N’Diaye told her, “I’m getting hot, I want to jump in.”

“I was like, ‘You sure? Do you want to jump in?’ And he’s like, ‘Yeah, I want to jump in.’”

Tooman said N'Diaye gave her all his stuff and took off his shoes, and when her mom asked N’Diaye if he wanted a life jacket, he said, “No, I’m fine.”

“He jumped in feet first, denied the life jacket and everything, jumped in feet first and never resurfaced,” Tooman said. 

She said she took a video of the jump “because it was the first time that he had done something like that.” She has since turned the video over to the sheriff’s office.

“He looks back at the camera, smiles, and jumps in,” Tooman said of the footage. “After about 15 seconds, we hadn't seen him. I stopped the recording and everybody immediately jumped off the boat, jumped in, started looking for him. My sister scanned the whole bottom of the boat to make sure he wasn't under the boat or anything… There was no nothing.”

“He had a bright red shirt on and he jumped in and after he initially jumped in, we didn't see his red shirt again,” she added.

Tooman said that after about two minutes, her mom came back to the boat and called 911 and search and rescue. Search and rescue arrived “35 or 45 minutes” later—“the longest time of my life,” Tooman said. 

She noted that when authorities were called on July 24, they questioned everyone on the boat.

“They didn’t do, like, interrogation questions, I guess you would call them, but, they asked each one of us independently what had happened and what we saw and what we knew,” she said. “But, because we have the video of what had happened, they didn’t do a ton of questioning because they kind of saw what they needed to see in the video.”

“There was no arm flinging. There was no bubbles… That directs the sheriffs to believe that it could have been something medical when he jumped in, because there was no sign of struggle.” Tooman added. “The sheriffs are saying that that could have possibly sent his body into shock.”

White confirmed that. “One of our theories would be [his] not being used to water, and hitting this 60 degree water could debilitate a person,” he said.

“The responding officers did their preliminary investigation and there was, you know, no evidence of anything suspicious. And there was evidence to the contrary of that showing that this is a tragic accident,” he said.

Authorities said they searched the lake with cadaver dogs, which gave positive indications in the area where N’Diaye was said to have gone down. The search teams had “very, very limited visibility with their underwater equipment,” White said earlier this month. 

While police suggested there’s little mystery around the incident, N’Diaye’s friends and family are troubled by lingering questions, including why he would have jumped into deep water without a life vest.

“Mamadou cannot swim. He made it very, very, very clear,” said Dashaun Archer, his friend and teammate. “There’s no way that he’s getting into a river or lake that is 120 feet deep. It just doesn’t make sense to me.”

Dev Thompson, another friend of N’Diaye and Tooman’s former roommate at school, shared the sense of bewilderment. “All of a sudden, he wants to jump in the lake with his shirt on and he can't swim, no life jacket?”

Miles Smith, N’Diaye’s coach at Northern Vermont, expressed frustration that police have not offered more details about the incident. “I can’t sleep at night because none of these things even add up to making sense,” Smith said. 

N’Diaye’s family told The Daily Beast they learned he was missing when the Prince George County Police knocked on their door, around 1 a.m. on the morning of July 25. 

On Aug. 2, nine days after the lake trip, his mother, Aïssata Traore, other relatives, and Diallo flew to Montana on a quest for clarity and closure. They visited Lake Koocanusa with authorities, and White played video that shows N’Diaye descending into the water.

Speaking through a translator, Traore told The Daily Beast “he looked scared” in the video she saw.

Yenaba Toure, Mamadou’s cousin, who also saw the video, said “he clearly jumped on his own.” She also said she heard others encouraging him, “Jump! Jump! Jump!” 

“I thought he was a little tense and anxious,” she said. 

“He did look nervous,” Capt. White told the Daily Beast. 

Tooman, who had returned to school by the time of the family’s Montana visit, told The Daily Beast that she was traumatized by N’Diaye’s disappearance. She said she had cried so much the first two weeks that “tear ducts in my eyes felt bruised.” She said she was in therapy, and that she had been harassed by students and N’Diaye’s teammates, who suggested “that it was all my fault and that we shouldn’t have let him jump off the boat, saying that I was racist, that my family is racist.” 

Tooman said that she was having nightmares, but being back in Vermont helped by “having people around and being able to have a good time with friends, and not just sit there and think about it and cry about it.”

“Having people that loved both of us and grieving with them has helped a lot too,” she said.

When asked why she thinks N’Diaye jumped in, Tooman said: “I honestly don’t know… I don’t know if he learned how to swim at the college and his family just didn’t know, and that he was saying the truth or... We really just don’t know.” 

She added, “And like the sheriff said, ‘Unfortunately, he was an adult, made an adult decision, and we’ll never know why it turned out the way that it did.’”

Speaking on behalf of the N’Diaye family, Diallo said the family had sent the sheriff a list of 22 questions expressing ongoing frustration and uncertainty. He told The Daily Beast that while police may believe the video of the young man jumping off the boat means he accidentally drowned, “that is for us not conclusive.”