A 60-year-old man convicted of raping and sexually grooming his mentally challenged stepdaughter has been sentenced to life imprisonment.The man was sentenced in the Gauteng High Court in Johannesburg on Thursday for the rape of a 23-year-old close relative between 2008 and 2016.He was also sentenced to 16 years for sexually assaulting and grooming her and other acts.He was convicted in May of rape, sexual assault, sexual grooming and exposing the stepdaughter to child pornography.The victim is clinically diagnosed as having the cognitive abilities of a 6-year-old girl.Handing down judgment, Judge Francois Du Plessis said the accused abused the trust the victim had in him."Although he was charged with and convicted of one count of rape, it is clear that the complainant was raped on more than one occasion during the period 2008 and 15 April 2016," Du Plessis said.He said the sexual abuse started when she was 13 years old and lasted until she was 19, when she first disclosed what was done to her.Du Plessis added that it was clear that the accused groomed the child by showing her pornographic videos and also exposing her to masturbating.During sentencing, the convicted rapist maintained his innocence, claiming that the victim and her mother were lying and that she had been coached.Aggravating circumstances overshadowed the mitigating onesDu Plessis said it was an accused's right to profess innocence but in a case such as this one, that may reflect negatively."In my view, what may, however, be regarded as aggravating, is his persistence in representing the complainant and [the mother] as liars. He went so far as to relate certain allegations which have not been produced in this trial on the merits," the judge said.He said the accused's allegations were false and humiliated and degraded the victim and her mother.The accused wanted a non-custodial sentence on the grounds of his age and medical condition, arguing that there were no psychiatric services available in prison.However, evidence the State presented indicated that there were such services available.The accused also argued that the court should be lenient because of poor conditions in prison for a person of his age. However, Du Plessis said the conditions in jail were a burden to all prisoners and a matter for the government executive to address.Du Plessis said after considering all the factors in the case, the court was of the view that the aggravating circumstances overshadowed the mitigating ones. ReliefThe mother of the victim has welcomed the sentence, saying she is pleased that the accused will never be able to hurt any other child, although no amount of punishment handed to him will undo what he did to her daughter."[She] suffered severe post-traumatic stress, and she will be going into therapy as from January. She is better now. "She was very determined to tell the judge her story. It was very important that he goes to prison for life. I will be very relieved to tell her that he is now off the streets and can't harm any other children again," she said after the proceedings.Women and Men Against Child Abuse advocacy manager Ngaa Murombedzi said the organisation was happy that the judge held onto important details relating to the victim, saying the trauma will always be with her at a level of a six-year-old. "We want to commend the judge [who] considered [her cognitive ability] as being the strongest aggravating factor although he said issues of age are not for the judiciary to decide," she said. Murombedzi added that the organisation would like punishment for crimes against child and gender-based violence to be a deterring factor.- The man cannot be identified to protect the identity of the victim.