James Rondeau, the president and director of the Art Institute of Chicago, has taken a voluntary leave from the museum after an incident on board a flight to Germany last month.

During the incident, which occurred on April 18 and was first reported by CBS News, police were called to United Airlines flight 953 after it landed in Munich from Chicago, following reports that Rondeau had stripped off his clothes. CBS reported that the incident occurred after he drank alcohol and took prescription medication.

A spokeswoman for the Art Institute on Saturday confirmed that the report was accurate and that Rondeau had taken a leave from work. In a statement, the museum said: “The Art Institute takes this very seriously and has opened an independent investigation into the incident to gather all available information.”