A teenager who is accused of the murder of Polokwane pupil Thoriso Kgomo has caused outrage after posting a video of himself from prison.In the video, which has been doing the rounds on social media, the teen can be seen in what looks like a prison cell and can be heard boasting about being arrested for the second time as he gives a tour of his prison cell."Round two, I have been arrested for the second time. You know what guys, life inside prison is tough. You thought life was easy. But I am going to be fine. I'm coming back soon and I will show you sh*t," he threatens in sePedi.In another video, the teenager films his prison cell and displays his prison bed and toilet as he brags about how comfortable his cell is.According to News24, the 17-year-old, who is accused of stabbing Grade 12 learner, Thoriso Kgomo to death, was out on bail on a rape charge at the time of the killing.The deceased, who was a pupil at the Northern Academy in Polokwane, was attacked and stabbed in Zone 3, Seshego, around 02:00 on Thursday and taken to hospital in a critical condition.The accused, a school dropout, was arrested on Sunday and will remain in custody until his next appearance for the murder charge on January 30.Read More: Boy, 17, accused of killing matric pupil while out on bail for rape caseSpeaking to DRUM, Brigadier Motlalefa Mojapelo said that the police were investigating where and how the video was taken, as cellphones were not allowed in cells."We are aware of the clip and we are currently investigating the matter. As you know, that youngster was out on bail of R700 when he killed Thoriso and is scheduled to appear in the Seshego Magistrate's Court on February 27. We don’t know where and when the videos were taken, which is why we have launched investigations to determine where it was done," he said."The videos seem to be taken from inside, but we don’t know where and when exactly," he concluded.Social media users expressed their outrage over the video, with many urging politicians to intervene.