Another eye witness account on what happened at BERSIH 3.0 and suspicions over who had rolled back the razor-bladed wires ("barbed" wires). Further confirmation that violence was probably planned and encouraged by authorities, from a commentator's comment over at Haris's People's Parliament blog:

I was at D Merdeka. But was at the front of DBKL when the melee started. But my brother and nephew were close to the truck on which were Anwar and Ambiga. According to my brother Anwar had gestured moving on towards Raja Laut. Ambiga had gestured that the sit in was over. It was about then that the barricades were breached. My nephew who was close to the breach felt himself pushed through it and he was in. The cops up front had receded. The major question my nephew has burning in his mind is, how come the razor wires were rolled up rather neatly and left lying by the side like as if someone who is familiar with piling it up had done it.
There is a tie up between the time the breach happened and the time Ambiga announced the rally over.
Until then any agent provocateurs would have remained quiet, thinking their job to begin only at 4.00. But when Ambiga prematurely announced the rally over the breach had to happen. According to a friend who also made through the breach at the Raja Laut entry point, discovered the cops missing. My brother finds all the DBKL staff locked in their building.
Later on at night, past 9.00pm there were 3 identical looking buses parked along Jalan Ipoh, in front of the Police Station that is under reconstruction. They had 1 Malaysia insignias on them. I saw 3 guys in mufti and another 3 in BERSIH T shirts chatting away. Agent Provocateurs? I wonder.