Aleksandr Zakharchenko, leader of the self-declared Donetsk People's Republic, or DPR, in eastern Ukraine, was killed on Friday after he was targeted with a bomb while dining at a restaurant in Donetsk.

Who is responsible? It is likely to be one of three factions.

The first possibility is the Russian government. Although the DPR is presented as an independent birthing of Ukrainian separatist sentiments, it is in fact a front for Russian intelligence operations. As a consequence, DPR leaders either follow orders from Moscow or they find themselves purged. Sometimes the purging is peaceful, as in the case of the formerly powerful DPR militia leader, Igor Strelkov. Other times the purging ends with loss of life.

Russia's interest in Zakharchenko’s demise might be found in his unstable personality, arrogance, and less than significant intellect. The Russians like people they can control but who also fill the role assigned to them. Zakharchenko perhaps went too far outside of the Kremlin’s comfort zone. And Russia certainly has no qualms about killing its adversaries in Ukraine, as well as any number of innocents.

Zakharchenko might also have been targeted by other interest groups in eastern Ukraine's Donbass region. Because of the Donbass area's longstanding position as a center for organized crime, it is feasible that Zakharchenko was targeted because others wanted to get their hands on money-making opportunities that his DNR leadership position afforded. Alternatively, he could be another victim of power struggles between the DNR and the Luhansk People's Republic - a similar creation of separatists. The Kyiv Post has done excellent work documenting these power struggles.

The least likely possibility is that the Ukrainian government pulled this off. Russia has immediately and aggressively blamed Kiev for this incident, but that actually lends more credibility to Russian responsibility. After all, Russia might have killed Zakharchenko to use his death as a cause for escalation. And while Ukraine's SBU intelligence service has engaged in some odd antics in recent months, this assassination would represent a major escalation -- one that Kiev would fear might provoke Russian reprisals that it can't handle.

There is no question that tensions are rising in eastern Ukraine. An escalation in fighting between Russian-supported interests and the government is increasingly likely. And Zakharchenko's demise may be a precursor to that development.