thank you very much for the clarifications
Neuechatel is Neuchatel-en-bray
Envernay is I think Envermeu (I live in Envermeu)
I've already seen this mistake in Norman R. Franks' book.
another source tells me that Kennedy was a victim of Hptm Herbert-Felix Bolz.
"26 Sqn Mustang AG536 MIA. F/L Donald Newton Kennedy b. Haut-s-Mer ca. 0600 by Hptm Herbert-Felix Bolz II/JG2 FW190".
some parts recovered at the crash site
https://zupimages.net/up/18/07/i8cq.jpg
https://zupimages.net/up/18/07/wzp3.jpg
https://zupimages.net/up/18/07/1akh.jpg
https://zupimages.net/up/18/07/qtj7.jpg
https://zupimages.net/up/18/07/ui87.jpg
Thank you all, I'll keep you posted on my research.
Alexis