RHINELANDER - Brandon Darnick appeared in court Monday for a jury trial after being accused of first-degree child sexual assault.
Six years ago, police didn't feel they had enough evidence to charge Darnick with child sex crimes.
The case started with a police investigation in Dec. 2013.
The boy's mother called police and said her son complained of a sore bottom that hurt when he tried to use the bathroom.
The child complained of a "doctor" putting his butt inside of his belly while he was in the care of others, but couldn't go into detail of the identity of the "doctor."
The mother testified in court Monday and said she rushed her child to the Ascension Saint Clare's Hospital in Weston after being referred from Howard Young Medical Center in Minocqua.
"He said the doctor put his butt inside of his belly and pointed to his butt," said Sexual Assault Nurse Examiner Alexandra Zopel.
Last year, the child's sexual assault kit was tested as part of a statewide effort to catch up on a backlog in the state.
After the kit was tested, it tied Darnick's DNA to the sexual assault.
Zopel examined the child and said the mother complained of changed behavior and noticed signs of trauma.
"When she tried to put him down for a nap, he was fussier than usual," said Zopel. "He didn't want to put on his pull up and when she did assist him to put on his pull up his bottom was red."
Darnick maintained his innocence and said he was alone with the boy behind closed doors.
The trial is set to wrap up on Friday.