Bayu Marhaenjati – The Betawi Brotherhood Forum on Tuesday attempted to launch an attack on the rival Pancasila Youth group – but unwittingly vandalized property belonging to a third group instead.

West Jakarta Police Chief Sr. Comr. Suntana said on Wednesday that 15 members of the forum, known as the FBR, had been arrested. Among them was a man identified as L., who police say is an FBR leader from the Tambora area.

Suntana said L. ordered his members to attack the Pancasila Youth (PP), which the FBR leader suspected had vandalized his food stall.

L. on Tuesday evening rallied 50 FBR members armed with machetes and swords. The group then rode on motorcycles, seeking out PP members and targeting their observation posts. The mob attacked one post in Penjagalan, West Jakarta, not realizing that it belonged to the Betawi Communications Forum (Forkabi), another group that has also had disagreements with the FBR.

"[FBR] vandalized and set fire to a Forkabi post. They thought it was PP's," Suntana explained, adding that the FBR also vandalized two food stalls, the owners of which are unclear. "Fifteen FBR members who were involved in the act have been arrested. We also confiscated swords, machetes and other sharp weapons," the officer said.

Police have been trying to quell steadily rising tensions between the FBR and the PP following the murder of 36-year-old Muhidin, an FBR member, in Ciputat, Tangerang, last month.

There have been reports that the FBR has been involved in a series of retaliatory attacks on people believed to be connected to PP following Muhidin's murder. Clashes between PP and the FBR are common and often involve control of turf and illegal parking areas.

It is likely that Tuesday's incident will further escalate tensions between the FBR and the PP, as well as create fresh strains between the FBR and the Forkabi.