Police arrested a homeless man and were searching for three other men who they said robbed a man at knifepoint in Coram early Sunday.
Four men, including Armad Johnson, 25, assaulted the victim, police said, stealing his leather coat and two diamond earrings while threatening him with a knife. The robbery occurred at 16 Middle Country Rd.
The victim suffered injuries to his face and was taken by police to St. Charles Hospital in Port Jefferson, where he was treated and released.
Johnson, 25, was arrested and charged with robbery in the first degree. He is being held at the Sixth Precinct and is scheduled to be arraigned Sunday morning at First District Court in Central Islip.