Azyumardi Azra, dean of the State Islamic University in

Azyumardi Azra, dean of the State Islamic University in Jakarta, described the verdict as "a disappointment" to Ba'syir's supporters as well as to the police and prosecutors.

"The police and prosecutors only presented circumstantial evidence instead of hard proof," he said.

"I think the lack of professionalism of the police in preparing the evidence file and presenting credible witnesses are the reasons why the judges could not do much in producing a satisfying verdict," Azra told AFP.

But he said the verdict was not a setback for the government because it served as "a strong signal" that it would not tolerate terrorism by radical groups in the country.

He speculated that the four-year prison term was passed due to "pressure by certain parties" such as the Indonesian police.