"Did you ever see her injuries?" Tree asked.
"No, I did not," said Shepherd, who was called by the prosecution and appeared in court in a blue Weber County jail jumpsuit, with his hands and feet shackled.
Shepherd went to jail three weeks ago, when Judge Ernie Jones ordered the 22-year-old to serve the maximum sentence of 2 1/2 years in jail for his role in the swimmer's death. A jury found him guilty in December on three misdemeanor charges.
This week, the two other men who were on the boat that August day Colton Raines, 22, and Robert Cole Boyer, 30 are on trial.
All three were charged with class A misdemeanor obstructing justice. Raines and Shepherd also were charged with class A misdemeanor reckless endangerment and class B misdemeanor failure to render aid.
Shepherd testified that both he and Raines owned the boat that allegedly struck Fujimoto, a 49-year-old University of Utah medical researcher.
He testified that he still doesn't know whether the boat struck Fujimoto that day, or just got close to her.
"To my knowledge, to this day, we don't know if we hit her," Shepherd testified.
Shepherd said Raines was driving the boat when he swerved to the left because he had come close to a swimmer. Shepherd then took the wheel, and circled back to check on the person in the water.
After asking her three times if she was OK, Shepherd said, she finally responded with a "yeah," and appeared agitated with the trio.
"At that point, like I said, I felt like I was scolded, so I put the boat in gear and left," he testified.
Chief Medical Examiner Dr. Todd Grey testified Tuesday that it was unlikely that Fujimoto would not have been aware that she was severely injured, or that she would have told the three men that she was OK.
"These injuries are deep," Grey said. "They are devastating. They would have been very painful."
Shepherd admitted on the stand that the three men had consumed alcohol that day, but said he was never impaired. He said he never saw Raines or Boyer smoke marijuana.
Kelsey Kuch, who was on the boat earlier in the day, testified that Raines brought a small pipe and marijuana to the lake that day. She said Raines smoked, but couldn't remember if Boyer did.
Prosecutors and investigators have alleged that the three men concocted a story about what they did on the lake that day, leaving out their run-in with the swimmer.
But Shepherd said Tuesday that was never the case.
"I [wasn't] trying to fabricate a story," he said. "I told them [Raines and Boyer] the story I would tell [to police.]"
Shepherd initially told investigators he knew nothing about the swimmer, but eventually came to their office with his attorney, Glen Neeley, and confessed about the encounter.
Raines and Boyer have never talked with police.
Defense attorneys Rebecca Skordas and Greg Skordas took issue with Shepherd's testimony on Tuesday before he even took the stand, saying they were never informed that Shepherd had agreed to testify until Tuesday morning.
After prosecutors offered Shepherd immunity for his testimony, Shepherd said he decided to testify because he wanted to tell the truth, and did not want to be charged with contempt of court or obstruction of justice for not testifying.
"I just want to do the right thing," Shepherd said Tuesday. "Be honest, tell the truth. But at the same time, I don't want any prosecution or felonies."
Shepherd indicated that he planned to appeal his sentence, but has not hired a lawyer to represent him in the appeal. On Tuesday, he was represented by public defender Shawn Young because Neeley resigned from the case after Shepherd was sentenced.
The trial is expected to resume on Thursday.