A man who is behind bars for raping and murdering a woman inside a Tshwane government building is expected to have more charges added to his rap sheet after a News24 exposé revealed that he had access to a cellphone in prison.Piet Mabotja, who was sentenced to life imprisonment in the Gauteng High Court in Pretoria for raping and murdering Nomathamsanqa Regina Majola, appeared to be active on social media even though he has been behind bars since his arrest in 2018.On Thursday morning, News24 reported that Mabotja, going by the name "Peter Mabotja", posted images to a closed Facebook account that only shows when he updates his profile or cover picture.Most of the images, posted in February, show Mabotja wearing the same white, long-sleeved shirt, short pants and brown shoes. It is believed that the pictures were taken in Kgosi Mampuru prison, where he is currently being held.There is also an image of Mabotja posing in underwear at what looks like a bodybuilding competition, with Department of Correctional Services banners in the background.Image via Facebook/Piet Mabotja One of Mabotja's Facebook friends commented on the picture, asking if he was in prison and he replied: "Okay prisoners."READ | Man behind bars for rape, murder 'still using social media'The Department of Correctional Services told News24 that a full-scale investigation would be launched, adding that the existence of a social media account linked to an inmate and the images on the account, which appear to be taken inside the prison, were disturbing."What makes things worse, is that this inmate could also be engaged in other activities with the outside communities through social media," department spokesperson Singabakho Nxumalo said."Contraband does pose a serious danger, not only to our officials and other inmates in our centres, but the lives of ordinary citizens are also at risk. It is therefore something that requires us, as correctional services, to condemn it and take firm measures against those who smuggle items like cellphones."Image via Facebook/Piet Mabotja By Thursday afternoon, a search had been conducted. A cellphone belonging to Mabotja was found and confiscated."He will be charged, as it is a criminal offence to have a mobile phone inside a correctional facility. The investigation will also solicit information contained in that cellphone," Nxumalo told News24.SentencingIt appeared that the images on the Facebook profile were taken around the same time Mabotja was expected to be tried for Majola's rape and murder.During his sentencing on Wednesday in the Gauteng High Court, sitting in the Pretoria North Magistrate's Court, Mabotja wore a similar outfit to the ones he wore in the images posted on Facebook.He was sentenced to two life terms and an additional 57 years behind bars for a string of crimes committed between 2017 and 2018.In February, he pleaded guilty to several charges, including one count of murder and two counts of rape. His plea was accepted and he was found guilty.READ | Man gets 2 life terms for rape, murder of colleague and stuffing her body in shaftIn December 2017, just before Christmas, Mabotja lured Majola to a secluded area on the seventh floor of the Department of Agriculture, Forestry and Fisheries building in Tshwane.Mabotja was Majola's colleague. Both of them were contracted to work as cleaners in the Sefala Building.Once in the secluded area, Mabotja demanded that Majola have sex with him. When she refused, he raped her and strangled her to death, before dumping her body in a maintenance shaft.He also stole her cellphone and bank card, which he later used to withdraw R4 000 to pay for groceries at a shop in Watloo, near Mamelodi.Less than a year later, Majola raped another woman near Stanza Bopape Clinic in Mamelodi, in September 2018. She was with her boyfriend at the time. He also assaulted her boyfriend by hitting him over the head with the butt of his gun and stole two cellphones from him.News24 previously reported that Mabotja was out on parole at the time that he committed the crimes.He was found guilty of murder and attempted rape in another case and sentenced to 18 years in prison on 1 February 2007, but only served about eight years before he was released on parole, on 27 November 2015. His parole was supposed to end in 2024.