DORTMUND, Germany (AP)—German authorities have begun a sexual assault investigation against Borussia Dortmund defender Neven Subotic.The state prosecutor’s office in Dortmund says Subotic and three others are under investigation after a 21-year-old woman filed a complaint saying she was the victim of sexual assault following a private party at the Serbian’s residence. Subotic recently returned from two months out because of facial fractures. He won the Bundesliga title with Dortmund last season.