A 'sadistic' double murderer has been granted clemency by the Indonesia President Joko Widodo, while two of the Bali Nine ringleaders remain on death row. Just weeks after Andrew Chan and Myuran Sukumaran were denied clemency, Dwi Trisna Firmansyah had his death sentence reduced to life. The 27-year-old was one of three killers involved in the brutal premeditated murder of a shop owner and his school- aged son in April 2012,News Corp reported. Scroll down for video . A 'sadistic' murderer has been granted clemency in Indonesia, while Australian convicted drug traffickers Andrew Chan (right) and Myuran Sukumaran (left) remain on death row . While the decision, which was apparently signed off by Widodo on February 13 but only reached Firmansyah this week, has been praised by human rights groups, they have also said it highlights the inequalities in the judicial system. The lawyer for Firmansyah hopes he will be out from behind bars in the next few years. The 27-year-old, along with two others, allegedly planned to rob and murder a mobile shop owner in Pekanbaru. The trio broke into the man's shop and hit him over the head with a wooden bat while he was taking part in his morning pair. When the man's son tried to come to his father's aid he was also killed. The pair may be waiting months for their execution as other prisoners pursue lengthy appeals . After the murders the group stole the shop owner's car, along with a number of mobile phones and phone credit. Their appeal to the Supreme Court earlier this year failed, but Firmansyah was then shown mercy amid the Indonesian President's tirade against convicted drug smugglers. This comes after it was revealed Chan and Sukumaran could have their executions delayed for months as other death row inmates take on lengthy court appeals. It has been revealed by the Indonesian attorney-general Muhammad Prasetyo that the execution of the Bali nine duo will take place at the same time as several other foreigners on death row. This could delay the pair's execution as all avenues of legal appeal for the other eight convicted drug offenders must be exhausted before their death sentence can be carried out. The Indonesian Governor-General has said the death row inmates will be executed 'simultaneously' Myuran Sukumaran, left, and Andrew Chan, right, will be put through an 'assimilation' process as they prepare to face the firing squad . This means Andrew Chan and Myuran Sukumaran may have months to wait before they face the firing squad. Mr Prasetyo also claims the death row inmates will be put through an 'assimilation' process which he believes will help them mentally prepare for their death. 'They will be accompanied by religious figures until they're truly ready,' he said. The two men are currently being held in isolation cells where they are able talk to each other. Their interaction with other inmates is limited to one Nigerian who is also on death row. Prison authorities claim there's been no order to move Mr Chan and Mr Sukumaran from 'Death Island' even though the appeals process may be lengthy. Although the appeals process may be lengthy there have been no orders to transfer Mr Sukumaran and Mr Chan from the prison referred to as 'Death Island' President Widodo is adamant he will show no leniency to drug offenders caught on his shores . The pair's lawyers will return to Jakarta court on Thursday to challenge President Widodo's decision to deny clemency to all drug offenders. Their last appeal was adjourned until March 20 as the president's representative did not have the required legal documentation. Two weeks earlier, the Administrative Court dismissed their argument that President Widodo failed to consider their rehabilitation. The claim was rejected on the grounds that the court had no authority to overturn presidential decree. The Australian government, alongside several notable public figures, have made repeated pleas to spare the lives of Mr Chan and Mr Sukumaran. Foreign Minister Julie Bishop has written to the Indonesia government offering to cover the cost of life imprisonment for the condemned pair if they agree to call off their executions. Ms Bishop has offered to cover the costs of life imprisonment for the condemned men, if their lives are spared . Ms Bishop is yet to receive a response. The families of the convicted drug offenders have been allowed to visit twice since their transfer to Nusakambangan island last Wednesday, with their next visit scheduled for Monday. This news comes as a prisoner art exhibition and auction featuring Mr Sukumaran's work was dramatically cancelled after Kerobokan prison authorities said they didn't want to associate with the prisoners pending execution. The Kerobokan Jail governor Sudjonggo ordered all 92 prisoner paintings to be removed before the exhibition commenced. He claims that authorities we unaware the event was advertised as a tribute to Mr Sukumaran, a former art teacher at the prison. A chilling self portrait of Mr Sukumaran that would have been displayed alongside other prisoner art at the Kuta exhibition . The exhibition featuring Mr Sukumaran's most recent work was cancelled as prison officials say they didn't want to get caught up in the politicised executions . 'It is cancelled because we do not want to be involved in any matters relating to Myuran. I have conveyed to the organisers about that and they promised that none of Myuran's paintings will be at the exhibition,' Sydjonggo said. 'It doesn't mean that we are forgetting Myuran. No. But we just don't want to be involved in the discourse about the execution which is now already politicised,' he added. The money raised by auctioning off the prisoners artwork was to be used to continue funding the art program at the Kerobokan prison as well as building a gallery intended to showcase the works of ex-prisoners who were mentored by Mr Sukumaran. Mr Sukumaran has been unable to paint since his transfer to 'Death Island' however prison authorities say Mr Sukumaran will eventually be allowed to have his art materials. Mr Sukumaran was a highly respected art teacher while he was detained in Kerobokan prison .
Condemned Bali nine duo to be executed with other death row inmates . Indonesian Attorney-General reveals plans for 'simultaneous' execution . Prisoners could be waiting months as all appeals must first be exhausted . They'll go through 'assimilation' process to prepare themselves for death . The pair's appeal for clemency will recommence Thursday March 20 . Art exhibit featuring Mr Sukumaran's work was cancelled by prison official . Authorities say they don't want to get caught up in politicised execution .