Iraqi premier claims members of Kurdish police were involved, raising prospect of political motives behind the May 2 attack.
The attack echoes a series of assassinations targeting northern oil officials in 2015.
The bombing raid targeted a PKK affiliate, but KRG Peshmerga were killed.
A long-serving Iraq security official discusses the future of the al-Hashid al-Shabi program and outlines a proposal for providing security services to investors.
The civilian death toll is rising as IS militants use human shields in their ruthless defense of western Mosul.
Security forces affiliated with Kurdistan's ruling KDP party have deployed near several PKK-heavy areas, raising the prospect of more violent confrontations.
"Black Force" special police left key energy sites in Kirkuk, but the political tensions that produced the dramatic showdown remain unresolved.
Four Hashid soldiers were killed in an attack late Monday, when IS insurgents set multiple wellheads on fire.
"Black Force" special police took over the North Gas Company headquarters Sunday, and continue to occupy the IT-1 station, as tensions over Kirkuk energy resources escalate.
Proxy forces backed by Kurdistan's ruling KDP party and the PKK fought a four-hour battle Friday, foreshadowing a new phase of volatility for territory liberated from IS.
