The GUR just confirmed the operation. A Russian Mi-8 carrying spare parts for fighter jets was lured into Ukraine in an operation that lasted over 6 months. Two crew members (unaware where they were heading) were reportedly eliminated while the Russian pilot was kept unharmed. He is reunited with his family that was taken to Ukraine earlier.
"Official information will be forthcoming. In advance, there is such information. We need to wait a little, the work will be done, including the crew. Everything will be fine, there will be news," said Andriy Yusov, a representative of the GUR.
Maybe there was, and maybe there wasn't. Defecting to the country you're at war with is an incredibly risky endeavor, especially if you're taking ~$10m worth of military hardware with you. Could be that the crew member(s) who survived just erred on the side of caution and killed anybody they weren't 100% sure about.
Could also be that they defected and reported that they were killed, to protect their families from retaliation.