KYIV -- The Ukrainian Security Service (SBU) says a second person has been detained in an alleged plot to assassinate Russian journalist Arkady Babchenko, an outspoken Kremlin critic, in Kyiv.

The deputy head of the SBU's main investigative department, Bohdan Tyvodar, told a June 15 news conference that the suspect, a Ukrainian man, was detained two days earlier.

Tyvodar played what he said were recorded phone conversations between the suspect -- identified only as "Citizen T" -- and the alleged organizer of the plot on Babchenko's life, Ukrainian businessman Borys Herman.

In the recording, the authenticity of which could not be immediately confirmed, two male voices are heard discussing how to travel from the Russian city of Rostov-on-Don to Kyiv via Istanbul to avoid detection, as well as how to procure weapons.

"At present, there are sufficient grounds for suspecting Citizen T of involvement in the preparation of terrorist acts," Tyvodar said.

Tyvodar said the suspect was also being held on suspicion of illegal handling of weapons and explosives.

The SBU staged Babchenko's murder on May 29, claiming the extraordinary measure was the only way to save the journalist's life and catch the organizer it claims was tasked by Russian security services.

After Babchenko turned up alive at a SBU press conference the following day, the SBU said it had detained Herman, who the agency said oversaw the alleged plot.

Herman is alleged to have promised $40,000 to a would-be assassin for the killing of Babchenko.

The alleged would-be killer, a former Ukrainian monk turned army veteran named Oleksiy Tsymbalyuk, said he went to the SBU after Herman approached him. Tsymbalyuk says he worked with the agency to foil the plot.

Herman was remanded in custody for 60 days by a Kyiv court on May 31.

With reporting by Christopher Miller in Kyiv, Zn.ua, and 112.ua