WAILUKU » A trial has begun for a Maui woman who is accused of injuring a toddler who attended her toilet-training "boot camp."

A pediatrician testified Wednesday on the first day of the nonjury trial of Rebecca Stapp of Waiehu, the Maui News reported.

Stapp, 39, has pleaded not guilty to a charge of third-degree assault on the boy.

Pediatrician Norka Wilkinson testified in Wailuku District Court that severe to moderate force would have been used to inflict injuries to the buttocks, thighs, lower back and groin area of the child. The boy was about 17 months old when the pediatrician examined him on May 2, 2013, at Kaiser Permanente’s Maui Lani Clinic.

"What struck me was it was in a very particular area . . . the fact that it was close to the core of the body," Wilkinson said. "Those are areas that are common to be non-accidental. Those would be bruises that would be very suspicious in my opinion."

Stapp’s attorney, David Wiltsie, asked the doctor if diaper rash could have caused what was shown in photographs presented by prosecutors.

"It doesn’t look like diaper rash to me," Wilkinson responded. "It looks like bruises."

Deputy Prosecutor Justine Hura said in her opening statement that the boy was fine the morning of May 1, 2013, when his mother dropped him off at Stapp’s rented home, where she ran Stapp’s Potty Boot Camp business. According to Hura, Stapp explained symmetrical black-and-blue marks on the toddler’s thighs near his groin.

The mother pulled over on the way home to examine her son more closely and found a large bruise on his back. The mother reported the injuries to authorities.

Hura said Stapp told police several stories about what happened when she was interviewed later that day.

"None of the stories are consistent with the injuries," Hura said.

The trial is set to resume early next month.