In a colorfully-worded post on Facebook, Melnikoff's Soul of Ukraine foundation alleges that the exhibition was destroyed "with the connivance of law enforcement authorities in Riga" on Sunday night.
"Riga police could not or did not consider it necessary to prevent the destruction," the post continues before threatening to draw the attention of the Ukrainian Rada and the US senate to the "shocking event".
"The Foundation draws particular attention to the fact that the destroyed exhibition bore the State Emblem of the Republic of Latvia."
The statement then demands that Riga City Council, which had granted permission for the exhibition to take place, should pay compensation as soon as possible in order to avoid litigation. The council should also reimburse the organizers for "moral damage" it says.
The post does not explain why the exhibition was left unattended for two consecutive nights even though organizers had promised police they would provide on-site security.
Police have appealed to the public for information concerning the identities of the vandals.
Melnikoff said on Sunday after the destruction of the exhibition that it would "open today at the Freedom Monument", while according to a correspondent at LTV7 channel there has been no activity nor at the previous site of the exhibition nor at the Freedom Monument.
Meanwhile, LSM has uncovered a few more facts about the colorful Melnikoff that are perhaps worthy of consideration given his claim to be both strongly anti-Putin and a world famous photographer of high standing.
A publicity image for the People of Maidan exhibition on the Soul of Ukraine website contains a striking selection of cut-out faces on a yellow background, with the word 'Melnikoff' emblazoned across the top, clearly indicating that these are his pictures.
However, simple internet searches reveal that at least some of the images are not by Melnikoff at all.
The sinister image of the man in the balaclava at bottom left is simply a horizontally-flipped version of a picture available at the Shutterstock online photo library.
Next to that image is an even more impressive image of two men in armor striding towards the photographer. In this case, the photographer is not Sergey Melnikoff but internationally-acclaimed photojournalist Evgeny Feldman of the Associated Press newswire.
The final image of the gallery showcasing Melnikoff's book of Maidan photos - an incredible shot of riot police in flames - is demonstrably not his. It is just a cropped version of this shot by another Associated Press photographer, Efrem Lukatsky, with the color saturation turned up.
LSM has not yet verified how many of the remaining faces were shot by Melnikoff, but if copyright has been infringed, it would be of embarrassment to the Latvian Foreign Ministry, which officially supports the exhibition.
Finally - and perhaps most bizarrely of all - despite professing a deep hatred for Russian President Vladimir Putin, a promotional YouTube video produced by one of Melnikoff's own companies and titled "Maitre. Sergey Melnikoff, a Man with a Dream" shows Melnikoff alongside Putin enjoying a cosy chat in a sun-drenched hilltop fort - though admittedly the still image (at 4 minutes 17 seconds into the film) does look suspiciously like a faked composite.