Later he was relocated to Hvardiiske in Crimea where in 1991-1998 he served in the Military Aviation Forces of Black Sea Fleet (Russian Federation).

In his official biography Yakymenko claims that he worked in the Security Service of Ukraine in 1999 to 2007 in leading positions, yet does not disclose in what exactly and without any details.

[5] On February 20, 2014, snipers and special assigned units of the MVS and SBU appeared on the streets of Kyiv.

On February 22, 2014, the Ukrainian parliament installed a parliamentary commissioner to check the SBU's activities, Valentyn Nalyvaichenko who the next day announced that all leadership of Security Service of Ukraine quit.

A few days after the February 2014 Ukrainian revolution, Yakymenko, along with about 15 former SBU top officials, surfaced in Russia.