The murder occurred in Kiev in 2010, outside the 4 room furniture store founded by the two businessmen in 2008, after which the dual citizen of Armenia and Russia was arrested in Russia (Aloyan is his name as it appears in his Armenian passport; after getting married, he adopted his wife's surname, Suslov).
Nevertheless, it's clear that as long as such people serve in the police force, no one is safe from getting punched in the nose while being detained by police and not resisting.
Now, perhaps, the EU simply wishes to diplomatically show the Armenian authorities that their decision was wrong. No one will punish Armenia. The EU is presently engulfed in the problems of Moldova and Ukraine and is satisfied with cooperation with Georgia.