Under the Dome by Stephen King

Under the Dome is a novel by Stehen King, published in November 2009. Under the Dome is a partial rewrite of a novel Stephen King attempted writing twice in the late 1970s and early 1980s, under the titles The Cannibals and Under the Dome.
Police Chief Howard "Duke" Perkins is soon killed when his pacemaker explodes after getting too close to the barrier. This removes the last significant opposition to James "Big Jim" Rennie, used car salesman and the town's Second Selectman. Big Jim exerts significant influence within Chester's Mill, and seizes the opportunity to use the barrier as part of a power play to take over the town.
Big Jim appoints one of his cronies, the incompetent Peter Randolph as the new Police Chief. Police Chief Howard "Duke" Perkins is soon killed when his pacemaker explodes after getting too close to the barrier. This removes the last significant opposition to James "Big Jim" Rennie, used car salesman and the town's Second Selectman. Big Jim exerts significant influence within Chester's Mill, and seizes the opportunity to use the barrier as part of a power play to take over the town.
Big Jim appoints one of his cronies, the incompetent Peter Randolph as the new Police Chief. He also begins expanding the ranks of the Chester's Mill Police with questionable candidates, including his son, Junior Rennie, and his friends... (Summary by Wikipedia)