The Crown says George Gwaze's crime is inexcusable.
The 60-year-old denies the murder and sexual violation of 10-year-old Charlene Makaza in Christchurch in 2007.
His defence argues she died as a result of complications of HIV.
Crown prosecutor Brent Stanaway told the jury it's obvious George Gwaze is a well educated, good humoured man, but that is no defence.
"The Crown, as I said when I opened, is inexplicable and illogical but the Crown says regrettably, as has been proved, good men sometimes are proved to have done bad things.''
Mr Stanaway then told the court that there is no apparent motive for the crime, but it is not up to the Crown to prove a motive exists.
He told the court the injuries found on Charlene can't have been caused by anything but blunt force trauma.
"In fact, as shown in my submission, the evidence that she died of HIV is very poor.''
Mr Stanaway reminded the jury that this is not a trial by experts, but a trial by a jury and they should make a decision based on expert evidence as well as common sense and logic.
He told the court the crux of the case comes down to the cause of death.
"This trial is about whether those ano-genital injuries were caused by blunt force trauma or by HIV or whether Charlene died with, or of AIDS.''
Mr Stanaway told the jury that some of the experts have been questioned well beyond their area of expertise in this case.