Erwida Maulia and Rizal Harahap, Jakarta/Medan – Heads are rolling in the wake of the death on Tuesday of North Sumatra legislative council speaker Abdul Aziz Angkat after a protest that turned violent.

On Friday, National Police chief Gen. Bambang Hendarso Danuri said the North Sumatra and Medan Police chiefs would be dismissed for being "neglectful" in their duties to ensure security.

Despite the presence of police outside the provincial legislature in Medan, angry protesters managed to mob Aziz and assault him. Aziz died hours later, with police saying he died of a heart attack, while his son pointed out injuries to his body.

The protesters were enraged by the council's decision to postpone a plenary meeting to discuss a recommendation of the establishment of a new province, Tapanuli.

"We've made an internal evaluation and... yes, there were some [procedures] that the field [police] officers failed to carry out, and so we must mete out punishment," Bambang said after meeting with President Susilo Bambang Yudhoyono at the Presidential Palace.

Medan Police chief Sr. Comr. Aton Suhartono said although he had not yet heard news of his dismissal, he would still be involved in the investigation until the handover to the new chief. "If it's true, I accept the [decision]," he said. "I'm the one most responsible, I was there at the time."

A fact-finding team from the House of Representatives said in Medan on Friday that "early indications" pointed to "serious" lack of security during the incident.

In a protest in the city in 2007, police faced a similar situation, but they failed to refer to this incident, said the head of the team, Maiyasyak Djohan. At that time, council speaker Abdul Wahab Dalimunthe, who was also confronted by protesters demanding clarity on the Tapanuli issue, proposed lifting the impoverished western coast of North Sumatra out of isolation and poverty.

Friday's dismissals of the North Sumatra and Medan Police chiefs were not measures decided by "public pressure or political aims", Bambang said, "but simply for objectivity and professionalism".

He added that based on autopsy results, the death of Aziz, a provincial executive from the Golkar Party, was caused by an "excess" of the attack. Police also said the victim had recently undergone cardiac bypass surgery.

Bambang said 12 people had been named suspects in the case and charged with violating Criminal Code articles on, among others, provoking hostility and destructive actions. Police earlier said they had named 11 suspects; Bambang did not identify the additional suspect.

Reiterating earlier calls on a moratorium on forming new administrative regions, the President said he had asked regional council speakers to suspend talks on the subject following the "shameful" incident.

"Some regional expansions are a success, but others are not, especially if they are done in the interests of certain elites, either for economic or political motives," he said.