Fidelis E. Satriastanti – A British geologist has criticized the East Java Police for stopping its investigation into the mudflow disaster in the district of Sidoarjo.

In March 2006, mud began spewing from a crack near a gas drilling well operated by PT Lapindo Brantas, a company that is part of the Bakrie Group controlled by the family of Coordinating Minister for People's Welfare Aburizal Bakrie.

The government has blamed the mudflow on negligence during the drilling, but the company says the incident stemmed from a strong earthquake in Yogyakarta, hundreds of kilometers southwest of from Sidoarjo, two days before the mudflow started.

In dropping the case, prosecutors cited an absence of "visual proof" to indicate the drilling activities had caused the eruption, meaning they wanted concrete representation of the link between the well and the mud geyser.

Richard Davies, an expert on mud volcanoes that has been studying the Sidoarjo phenomenon since 2006, said he was surprised police dropped the case due to a lack of evidence.

"This question depends on what you deem to be 'proof.' In my opinion, the amount of evidence from the drilling site is sufficient that we can say that beyond all reasonable doubt drilling was the trigger," Davies said.

"We're 99 percent confident that drilling was the cause. Whether this is sufficient to bring prosecution is a question for the Indonesian legal system."

During three years of legal battles over the disaster, police have submitted their case documents four times to East Java prosecutors, but each time the dossier was returned due to insufficient physical evidence to establish a link between the drilling and the eruption.

Davies said key data comes from daily reports during the company's drilling operation. He added that no useful information would be available from the site after the eruption.

He said research has been conducted on the earthquake that occurred on 27th of May in Yogyakarta, but "it was too small and too far away to trigger" the eruption, he said. "The effect of Yogyakarta's earthquake is the same as changes in weather conditions: too tiny."

Rudi Rubiandini, a drilling expert from the Bandung Institute of Technology who was also an expert witness for the case, said there should be no need to visually examine the site because all the information needed would be contained in the drilling reports.

"It's just like an airplane crash. We cannot possibly see what happened other than to find the black box and read from it. This is the same thing with drilling activities. The black box is the daily drilling reports," he said.

Meanwhile, Ipung Mohammad Nizar, one of the victims, said police failed to asked local or international experts to support their investigation. "I don't think they have asked all the experts in this case, especially international experts," he said.

Davies was not asked to testify in the case, despite urging to do so from nongovernmental groups.