 He downed four more Spads in May, his fifth victory being one of the most significant victories; on 25 May 1917, he shot down and killed the man who was then the second highest scoring ace in the French Air Force, René Dorme.As Kroll's diary related, the two pilots had locked in a circling dogfight beginning at 5300 meters (about 17,400 feet) and devolving down to 800 meters (about 2600 feet).Dorme's Spad suddenly nosed over and barreled straight into the ground, bursting into flames upon impact.