Members of the Islam Defenders Front (FPI) roam freely despite a history of frequently taking the law into their own hands and attacking and burning buildings of other groups.
The latest attack blamed on this radical group took place Sunday. At least 70 people were injured in the assault on activists of the National Alliance for the Freedom of Faith and Religion (AKKBB), who were gathered to rally peacefully at the National Monument (Monas) in Central Jakarta.
However, no arrests were made by police after the much-condemned attack.
"The police have either so far been defeated by the FPI, or some police officers are working together with the organization for their own benefit," activist Rafendi Jamin of the Human Rights Working Group said.
He said that only with protection from the police had the FPI managed to survive despite the organization's record of violence.
Lawmaker Nadra Izahari of the Indonesian Democratic Party of Struggle concurred, accusing the police of letting the FPI operate outside the law.
He cited the attack on the AKKBB activists, saying the police failed to make serious efforts to counter the PFI's violent acts.
"We have reasons to believe the police and the FPI have mutually beneficial relations as the hard-line group has repeatedly committed violence without serious resistance from the police," Nadra told a group of activists calling for the FPI's disbanding at the House of Representatives.
Many observers have accused the authorities of backing hard-line groups, including the FPI, to counter the movements by pro-democracy and rights organizations or to shift public attention from crucial issues for political reasons.
"We should push for FPI members to receive punishment, but we should not let the problems shift our attention from key issues, such as the recent fuel prices increase and poverty," Hendardi of the Setara Institute said.
Since its establishment, the FPI has launched dozens of attacks on people or institutions it regarded as insulting or antagonistic to Islam.
In June 2000, some 300 FPI members attacked the National Commission on Human Rights (Komnas HAM) headquarters in Jakarta in a protest against the commission's report on the 1984 Tanjung Priok massacre. Several people were injured in the attack.
The FPI was also blamed on late night attacks of nightspots and billiard centers in October 2002, hurting dozens of people. The police reportedly did nothing to stop the attacks.
FPI leader Habib Rizieq Shihab was tried in 2002 and put in jail for seven months because of the incident.
In December 2006, two policemen were injured when about 100 FPI demonstrators attacked the Playboy Indonesia office in South Jakarta.
In April last year, 17 members of the United National Liberation Party (Papernas) were injured in an attack by the FPI during a rally against the newly passed investment law.