The Security Service of Ukraine (SBU) has classified information on the masterminds of the 31 June acid attack on Kherson activist and blogger Kateryna Handzyuk, the agency has told Ukrainian News.
In response to the news agency's inquiry, it said that its disclosure may harm the investigation.
In particular, the SBU is not saying whether Handzyuk has been cooperating with investigators and whether she has testified.
The SBU refused to say whether it had identified the mastermind of the crime and whether it was checking law enforcers' involvement in it.
Earlier, Prosecutor-General Yuriy Lutsenko handed Handzyuk's case from police to the SBU.