Billionaire Sergey Karshkov, the co-founder of international sports betting site 1xBet, has died in a Swiss hospital at the age of 42 from an alleged rare medical reaction to gadolinium, the contrast dye used in MRI scans.

Russian compatriot and fellow Cyprus resident Pavel Muntyan announced Karshkov’s death on Wednesday via Facebook.

hiding out in Cyprus since 2016

Karshkov, who once worked in a Russian internal affairs cybercrime unit, had been hiding out in Cyprus since 2016 after Russian authorities put him on their international wanted list for multiple offenses, including money laundering through 1xBet.

Headlines and Global News drew a dark parallel between the gambling kingpin’s death and those of other high-profile Russians “who have mysteriously died since the Russian invasion of Ukraine in February 2022.”

Muntyan’s Facebook comment that built “like a bull” Karshkov was in robust health and was just going for a check-up in Switzerland, adds to the mystery.

While readers of spy novels will no doubt conjure up images of silent shadows slipping into Swiss hospital rooms, the reality is while a severe allergic reaction to the dye nurses inject into patients prior to MRI scans is rare, the anaphylaxis can quickly escalate to cardiac and respiratory arrest and death.