I have the same problem, I am supposed to kill pirates in system Opala. No problem, I thought, as it has both navigational beacon and asteroid field. Several hours and many, many wanted fugitives annihilated later, my mission count still reads 6 pirates, not a single pirate kill. I tried everything I could think of - patroling navigational beacon and engaging ships fighting local authorities, lurking in all the asteroid fields, watching miners do their job and waiting for pirates to arrive (no criminal came), I pulled many wanted criminals out of warp and got their bounty and I was even pulled several times out of warp by other criminals and got their bounty too (noobs - I love them extra crispy
). No idea what else I can do to kill pirates.
Maybe get myself mining laser and refinery and start mining myself? Can *this* have better chance to get some pirates nearby?