He stayed with Saints for two years before leaving for Dumbarton in February 2005. He became their captain and had done well for them - despite their relegation to the third division.
Dempsie suffered back problems during his time at Love Street and only made a handful of appearances in season 2004/05. However, he was a decent central defender when fit and is surely a loss to the game, especially at such a young age.
All the best for the future, Mark!