Ukraine’s intelligence service, the SBU, said on Friday it intercepted phone conversations ‘in which the occupiers confirm that Russian troops are to blame for this tragedy’, the purported rocket attack that struck Olenivnka pre-trial prison housing Ukrainian prisoners of war 53 of whom were later proclaimed dead.

The SBU said the intercepted phone calls will be used as evidence for the ongoing criminal investigation.

The intercepted conversations show that the Russians allegedly had put explosives in the prison, prior to the attack, the agency said in a statement.

What makes the story fishy is uncharacteristic sounds for this sort of explosions.

‘In particular, none of the eyewitnesses heard any missile flying towards the correctional facility. There was no characteristic whistling, and the explosions occurred on their own.’

Online video footage also showed that the windows remained intact in some rooms of the facility, according to the SBU, which ‘indicates that the epicentre of the explosion was inside the destroyed building, and its walls took the hit from the blast waves, protecting some of the neighbouring rooms.’

The intercepted calls also have mentions of Grad rocket systems, which had been placed close to Olenivka prison and soon were heard firing although got no counter battery fire – it was confirmed by DNR separatists’ troops.

The SBU interim head stressed his agency will do everything in their power to hold to account all the persons involved in Olenivka massacre. ‘We will not forgive any Ruscist- all of them will get retribution.’