A 19-year-old man was killed early Saturday morning when the car he was driving crashed into a Fitchburg pond, according to police.Fitchburg and Westminster police responded to the crash near the intersection of Westminster Street and Industrial Road around 1 a.m. on May 30, Fitchburg police said in a press release. At the scene, officers discovered that the car had left the roadway and become submerged in a pond.