Death threats have been made against several Bayern Munich players via an anonymous letter, a police spokesperson confirmed to dpa on Tuesday.
"We are investigating on suspicion of threats and disturbing the public peace by threatening to commit a crime," said the spokesperson, who did not provide further details.
The Bild newspaper had reported the letter mentioned Robert Lewandowski, Manuel Neuer and Serge Gnabry by name and was received on January 12 by the second division club St Pauli Hamburg, who turned it over to the police.
The letter reportedly said "Save the league, save the sport of football. Fire and death to the dirty Bayern pigs."
Bayern did not want to comment on the incident.