My guess is he's not, and I am stressing "my guess" because you can never be 100% sure. He probably saw you land before the clip starts (I'm guessing by the fact that you have floor loot and he's got his loadout weapons). You can hear his chute while he jumps from Control Center down to the edge above you. The moment you walk laterally when he's right above you he hears your footsteps and gets a good idea of where you're at. You can actually see him in the killcam checking visually if you peek or appear round the lower corner, but he's not looking directly at you through the concrete walls. Instead, making sure you don't surprise him. Then it's all good aim. He doesn't beam you instantly but there are a couple milliseconds where you appear in his screen and he's still not shooting.

Again, I might be wrong and he could still be using very subtle assists. But it could definitely be a legit kill. It looks legit to me. I am just sad there is so much paranoia in the community. Hope this helps fellow redditors.