Murder! or Sherlock vs Jason

Don't expect a bloodless, BBC murder mystery with Harpers Island.  The story is based around a poor boy / rich girl wedding, where some of the guests have not returned to the island since a serial killer went wild seven years earlier.  Is the killer back from the dead? Some of the characters' demise don't hit too hard... they weren't on the show long enough to make much of an impression.  Towards the end, though, I kept hoping the killer would be caught before people I really liked met some nasty deaths.