applies the the ukrainians were responsible. a claim that ukrainian authorities have denied one senior official saying we are not a criminal state. fred pleitgen is in moscow. where do things stand on this investigation? reporter: a lot of this is still very much a mystery. at such dazzling time in russia as you have russia s special military operation, as they call it, in ukraine, going on. so there were, of course, someone in the pretty high echelons in russia who believe that maybe the ukrainians might be behind all this. but right now, it still remains absolutely unclear. the latest from the investigation is that they say the explosive yield of that charge was the equivalent of about 400 grams of tnt. they say the bomb was placed inside the car. they ve recovered some parts and sent it in for a forensic investigation as well. still very much unclear who might be behind all this. here s what we re learning. reporter: a car engulfed in a massive fire ball on a highway o
i don t think it is your normal terrorist group, for instance, the chechnyans or the rest of it. so a friend of the dugin family said darya was driving her father s car when it happened. she s been an outspoken russian nationalist herself. do you believe she was the target? do you believe it was her father who was the target? on was there suspicion that they would be potentially in that car? i think the suspicion so far is that he went off in a different car. the real target, what was the father, alexander, because he is, he s almost call for genocide against ukrainians. he s a eurasian nationalist, whatever that is. and he s pushing putin, at least on tv, if not personally, to wipe out ukraine. he s december missed in ukraine. he s looked at it as someone who