The detective who is leading whatis now one of the biggest murder hunts ever undertaken by Cleveland Police, returned to the place Ms Glass was last seen to make his personal appeal.
Hampshire Constabulary's Supt David Powell said he maintains an "open mind" about what happened to the teenager and is not ruling out murder or foul play.
While there is no doubt Littleton was profoundly affected by Martha Moxley's murder and its subsequent investigation, to what end his problems can be attributed to this event is uncertain.
The Vineyard recently had its first murder in 20 years, when a man from Oak Bluffs was stabbed to death in whatis thought to have been a drug-related crime.