A Schalke supporter submitted a complaint to police against the match officials who denied the club two penalties during Saturday's defeat to Bayern Munich.
Experienced referee Marco Fritz and video assistant Bastian Dankert have been accused by the supporter of fraud over their decisions in the Bundesliga encounter, police in Gelsenkirchen said.
Fritz turned down a pair of Schalke appeals for handball in the box - against Benjamin Pavard and Ivan Perisic - with Bayern leading by two goals in the second half.
Neither incident involved VAR intervention. Fritz later told German broadcaster ZDF he did not receive any alert of an error from Dankert.
The fan's protest to police was widely mocked on Tuesday.
"A Schalke fan made a complaint against the referee and video referee because of fraud," North Rhine-Westphalia Police confirmed on Twitter.
"Reason: two penalties that were not given against Bayern. Police are examining the case."
Another Twitter user who subsequently enquired about seeking police verdicts on other games was told by the force: "You can always contact us. We would also provide handkerchiefs if the last tears haven't yet dried."
In a sign the investigation was not being taken especially seriously, Schalke responded to the police statement by saying: "We've asked around internally. This was from none of us ... word of honour.
"The result of the investigation would still very much interest us, dear @polizei_nrw_ge!
"Possibly helpful: We know eyewitnesses who were at the scene of the crime at the time."
Bayern went on to win 3-0 courtesy of a Robert Lewandowski hat-trick, his first a penalty following Jonjoe Kenny's challenge on Kingsley Coman.
Schalke boss David Wagner expressed dismay over the officiating, telling reporters: "Honestly, I'm looking forward to an explanation."
