Aberdeen football club has been summoned to appear before a Uefa disciplinary committee after a fan set off a flare at a match in Ukraine.
The Dons drew with Dnipro to progress in the Uefa Cup
The incident happened before last week's game against Dnipro, which Aberdeen drew 1-1 to progress to the group stages of the Uefa Cup.
A spokesman for the Pittodrie club said they were confident it would not attract a severe punishment.
The fan will be banned from all further games, if identified.
A flare was ignited shortly before kick-off, in the Aberdeen supporters' section of the Meteor Stadium.
It was spotted by one of Uefa's match delegates and reported to the organisation.
A Uefa spokesman said: "A case has been opened against Aberdeen for the throwing of a missile.
"Uefa's disciplinary committee will decide on possible sanctions when it meets on 15 November."
Pittodrie officials appealed to fans who may have information about the identity of the culprit to come forward.
An Aberdeen FC spokesman said club officials were informed of the news while attending the Uefa Cup draw in Switzerland.
"We possibly could get a fine," said the spokesman.
"We are urging any fans who are aware who the culprit is to come forward.
"They can contact us in complete confidence - if they don't want to give their name that is not a problem.
"Aberdeen Football Club has a good name. We don't want it besmirched by one idiot."