SHANGHAI—The mysterious death in police custody almost a week ago of a low-level Chinese bureaucrat who challenged a land deal backed by higher-level officials sparked violent public protests in the central province of Hubei and a shake-up among the local leaders.

The violent clashes this week in Lichuan, suppressed by a heavy paramilitary presence, appear to mark the latest tumult in China over land rights. While such disputes have occurred for years, the issue has been especially prominent in recent weeks, as ethnic Mongolians...