German police said an arson attack on a mosque in the country’s capital left has blackened its entrance door, but nobody was injured. There have been more than 10 arson attacks on Islamic institutions in Berlin in the past year, and police said in a statement Saturday they are investigating whether this attack is linked to the previous ones. The statement said a passer-by saw the fire early Saturday morning and alerted police. It said officers and the witness contained the small blaze with the police car’s fire-extinguishers. The fire caused only minor damage. Police said a message was left next to the mosque’s door, but did not provide further details.