Selectmen have agreed to begin the search for a new police chief by looking internally. The opening is being posted at the Police Department for the 10 days ending this Thursday. The current police chief, Joseph Rebello, has announced his plan to retire in late January after serving eight years as the town’s chief. He is also winding up a term as president of the Massachusetts Chiefs of Police Association. As of last week, no candidates had come forward. If internal applicants do emerge by Thursday, the town can choose from among those people or open up the search to outside candidates.