The head of state continuously supports transparent investigation and said those conducting the attack must be punished, according to Daniel Sparingga, the president's special staff in charge of political communication in e-mailed message here, Friday.
The president encouraged the law enforcement process and emphasized that the rule of law must be respected, he added.
"No one should be immune to law in this country," Sparingga said quoting the president.
The head of state also instructed the National Police to eradicate thuggery and other criminal organizations to make the public feel safe, Sparingga added.
"All streets and public places must be clean from any kind of thuggery that could threaten life and property. People must feel safe wherever and whenever - either daylight or night. This is the moment to reiterate our commitment to the rule of law," Sparingga said.
Army investigators had confirmed that 11 members of army's special forces Kopassus were behind the killing of four detainees at a penitentiary in Cebongan, Sleman, Yogyakarta, recently.
"Eleven members of Kopassus have been involved in the raid at the Cebongan penitentiary. One of them acted as the executor and eight others as supporters while two others had sought to prevent their action," the chief of army investigators for the case, Brigadier General Unggul K Yudhoyono said at a press conference here on Thursday.
He said the attack was done spontaneously in response to the killing of Kopassus member chief sergeant Heru Santoso at Hugo's Cafe on March 19 and an attack on former Kopassus member first sergeant Sriyono by the four thugs.
In the past six days the investigators have visited several places including the penitentiary, the Yogyakarta Military Command and the Kopassus Group II headquarters in Karang Menjangan, Solo, and questioned 25 people.