Graham, Heather. Krewe of hunters #4

"For as long as it has stood overlooking New England's jagged coastline, Lexington House has been the witness to madness-- and murder. But in recent years the inexplicable malice that once tormented so many has lain as silent as its victims. Until now. A member of the nation's foremost paranormal forensic team, Jenna Duffy has made a career out of investigating the inexplicable. Yet nothing could prepare her for the string of slayings once again plaguing Lexington House--or for the chief suspect, a boy barely old enough to drive, much less kill. With the young man's life on the line, Jenna must team up with attorney Samuel Hill to pinpoint who--or what--is taking the lives of those who get too close to the past. But everything they learn brings them closer to the forces of evil stalking this tortured ground" -- from author's web site