She was nearly as dedicated a swimmer as she was a scientist, he said.
Fujimoto, 49, of Ogden, was struck and killed by a motorboat at Pineview Reservoir Sunday evening, police said.
She was with her sister at Spring Creek Cove, a quiet spot where she often swam, when they became separated, said Weber County Sheriff's Sgt. Dave Creager.
A neighbor heard her scream about 8 p.m. He paddled a rowboat out to her and called 911, but was only able to hold Fujimoto's head above water so she could breathe, he said.
"He was alone in the boat, talking to the dispatcher, and he was not physically able to pull her out of the water without dumping his boat," Creager said.
The motor boat's propeller apparently tore into her torso and lower abdomen, causing critical injuries.
When rescuers arrived, they pulled Fujimoto from the water and performed CPR, Creager said, but Fujimoto died before rescuers could reach land.
She was about 300 feet from shore when she was hit. The boat never stopped.
Sheriff's deputies are searching for the craft, and want to speak with three males who were seen in the area in a blue and white boat.
"There's a high probability they may have seen or heard or have information," about the collision, said Lt. Mark Lowther.
Meanwhile, more than a dozen of Fujimoto's co-workers gathered Monday to mourn.
"She taught me everything I know," Brooke Gaynes said through tears, her eyes rimmed in red. Gaynes, a lab technician who saw Fujimoto every day, said she'd been out of town before her co-worker's death.
Along with her science skills, Fujimoto was a good friend, Gaynes said, the kind who always remembered specific details about others' lives.
"She just really cared about people," Gaynes said.
Fujimoto's work on the breast cancer gene was especially important because she'd had her own brush with the disease several years ago, Bonkowsky said.
Fujimoto, a senior lab specialist who had worked at the hospital since 2003, had "not only the technical skills, but the art of being a scientist, [the ability] to take a small piece of DNA and do what needed to be done," Bonkowsky said.
It's not the only tragedy to affect University Hospital workers this summer. In June, 24-year-old nurse Brynn Barton was struck and killed while riding her bicycle on 700 East.
Twitter: @erinalberty, @lwhitehurst