Robert M. Edholm - test pilot McDonnell - sound barrier?

[Leendert]

The gravestone of (Major) Robert M. Edholm (1917-1988) has the inscription 'First Man to Break the Sound Barrier in an Airplane'.(see https://nl.findagrave.com/memorial/1...obert-m-edholm)

Not to refute this accomplishment, when, where and in what airplane would this have happened given the general acceptance that Chuck Yeager was the first person to do so?

Edholm (O-391775) was with HQ Materiel Command at Wright Field, Ohio during WW 2 and after the war test pilot for McDonnell Aircraft, St. Louis (MO) in types as the F2H Banshee (1947), XF-88 Voodoo (1948) and F3H Demon (1951).

Any info to shed a light here is welcome, thanks.

Leendert