Grave Surprise is the second book in the Grave Sight series.
"A college class gets more than it bargained for when Harper gives a demonstration of her uncanny talent. Instead of just finding one body in an old grave, she finds two: the original occupant and a recently deceased girl whom Harper had tried, and failed, to find two years previously. To dispel suspicions about her own innocence, Harper and her stepbrother Tolliver undertake their own hunt to find the killer-only to find yet another body in the same grave."- (Amazon.com)