A guy put a gun to a man's chest to make him hand over his wallet, phone and backpack around 8:40 p.m. outside 410 Mass. Ave., kitty-corner from the Orange Line station.
The guy then ran onto a Southwest Corridor path towards the Back Bay, although he may have gotten off the path at Greenwich Park.
He's described as black, mid-30s, wearing a ski mask and dark clothes. And he was carrying the victim's black Nike backpack.