Shibboleth: A perfect murder?

Where better to dispose of a body than in a grave-yard? The problem was planning a murder whole thing and getting away without suspicion. A murder is planned, all the pieces planned ahead and all undertaken whilst the husband is 3,000 miles away in America. Fifteen years later, a skeleton is found and identified and now the police need to find a murder. They look, first thing, at the e-husband, but his alibi seems unshakeable even through a murder trial.