Hello!
Some answers and notes
15-00 is direction expressed in Finnish artillery unit
piiru (Angular mil (Eng)/Strich (Deutsch)) which is 1/6000th of full circle (Not 1/6400 like usually). To direction 15-00 is to East.
At times JG 54 seems to have used German time and other times the Finnish time (+1 hour) during the Commando Kuhlmey period.
I/Kev.It.Ptri 15 was at Säiniö 19th June and left from there in the evening at time 18.20 (Finnish time). So it was transferring towards Karisalmi when the Grollmuss body was given to them. The unit arrived at Karisalmi 23.30 o'clock.
II/Kev.It.Ptri 15 was at Suur-Pero (about 5 km NE Säiniö) when it observed the 1/FW falling down.
Grollmuss was the only Focke-Wulf loss during the evening of 19th June so we can be quite sure 15 Kev.It.Ptri observations are of him.
9./KTR 1 or
Kenttätykistörykmentti 1 (9. Battery / Field Artillery Regiment 1) war diary makes interesting note for the 19th June:
The marchroute is now Huumola-Säiniö-Pero-Naulatehdas. During the march enemy aerial activity was very high up to Säiniö, when own planes appeared for cover.
"Marssitie on nyt Huumola-Säiniö-Pero-Naulatehdas. Marssin aikana vihollisen ilmatoiminta on hyvin vilkasta Säiniölle asti, jolloin ilmaantui omia koneita suojaksi."
Source:
http://digi.narc.fi/digi/view.ka?kuid=2768220
JR 25 or
Jalkaväkirykmentti 25 (Infantry Regiment 25) retreated through the same route under chaotic conditions, especially the II Batallion. It is likely that Grollmus was killed by their fire taken erroneusly to be a Soviet Shturmovik pilot.
I could not find any mention of the incident in the infantry unit war diaries. I checked the Company, Batallion and Regiment level diaries. Same thing for the
Erillinen pataljoona 14 (Detached Batallion 14) which also was retreating via the same route. JR 5 would be another, yet not very probable possibility. Their march route was different.
Mihail Bykov's Sovjetskije Asy (2008 book) gives four claims over Säiniö:
1 "Fokker" by Gretshka 159 IAP
1 FW-190 by Karpov 27 GIAP Southeast Säiniö railway station
1 Me-109 and 1 FW-190 by Tsirkov 196 IAP over Säiniö railway station
Alltogether there are at least 14 Soviet claims (2 "Fokker", 4 FW-190 and 8 Me-109) for the 19th June. Couple of more of the locations are not too far from Säiniö. Problem is that no times are given for the claims.
Real losses for the day for FinnAF was one Bf 109 shot down by AAA. This was Luukkanen/MT-417 when shooting down a observation balloon in the morning, pilot survived the crash on own side.
JG 54 lost two Focke Wulfs: Obfhr von Obernitz was shot down by a Il-2 gunner at mid day. He parachuted and was taken PoW. Released 1949. And then Grollmuss, shot down by Soviet fighter, parachuted and then unfortunately killed in error by some Finnish infantry man (men?). Like the I/Kev.It.Ptri 15 war diary says his body was in Finnish custody at Karisalmi in the night 19-20th June. No room for speculation of partisans etc.
Cheers,
Kari