BERLIN (AP) – German police said three people were slightly injured Monday morning when they were targeted with darts likely shot from a blowgun in the western city of Cologne.

Police said in a statement that a construction worker, a passerby and an employee of the city’s public transportation corporation were slightly injured when hit by darts several centimeters long near the city’s downtown Barbarossaplatz square.

Several police teams were investigating and looking for a perpetrator. Possible witnesses were asked to get in touch with Cologne police.