Mr Babchenko showed up at the news conference on Wednesday and thanked everyone who was mourning his death.
Before ushering Babchenko into the room, Gritsak said investigators had identified a Ukrainian citizen who allegedly was paid $40,000 by the Russian security service to organize and carry out the hit.
His reported murder had triggered a war of words between Ukraine and Russian Federation and sent shivers through the journalistic communities in both countries.
"I'm sorry, but there was no other way of doing it", Mr Babchenko said during Wednesday's conference.
Babchenko, a prominent war correspondent, is extremely critical of Russia's annexation of Crimea, and was forced to flee Russian Federation in February 2017 because of threats to him and his family.
Arkady Babchenko, who moved to the city past year following threats in his homeland, was sacked on after returning from buying bread and died of his injuries in an ambulance, local police said late Tuesday.
"I used to be a good soldier", Babchenko wrote in 2017.
However, the journalist has appeared at a news conference in Ukraine.More news: Northern Ireland abortion reforms 'a test of May's feminism'
Babchenko and the Ukrainian Security Service revealed that the whole incident had been an elaborate sting orchestrated to flush out a real assassin, who had reportedly been hired by the Russian government.
Police said he had multiple gunshot wounds on his back.
Two years ago Pavel Sheremet, a Belarussian journalist known for his criticism of his home country's leadership and his friendship with the slain Russian opposition leader Boris Nemtsov, was killed in a vehicle bomb attack in central Kiev.
Babchenko left Russian Federation past year and had told people that he feared for his life.
Moscow's annexation of Crimea and support for separatist insurgents in eastern Ukraine were topics on which the journalist was scathingly critical of the Kremlin.
Babchenko sparked a backlash in Russia for his comments in a 2016 Facebook post on a Russian military plane crash. "Like many dissidents I am used to abuse, but a recent campaign against me was so personal, so scary, that I was forced to flee".
He moved to Kyiv last fall, where he worked as a host for the Crimean Tatar TV station, ATR.
While studying law in Moscow aged 18, Mr Babchenko was conscripted into the Russian army and served during the Chechen wars from 1994-2000.