We normally (in British English) use 'break in' intransitively, and 'break into' with an object. The policemen therefore broke into the house, not in it. There is no difference in the force used, the damage done, or the motives behind the act, between 'break into (a building)' and 'break in'.
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AlpheccaStarsBreak in - a criminal activity.'Break in' is not necessarily criminal.