Legally, IF the officer had a reasonable basis, based on what he could legitimately perceive from outside your home, for his belief that there was fighting going on and hence lives were potentially in danger, he would be entitled to enter to address the situation and protect lives. That is so even if he as later found to be wrong, so long as his belief was legitimate and reasonable as of when he acted on it. Whether that was the case is a matter of the facts and circumstances; so the answer is, if the facts are more-or-less as the officer claimed, he well have been justified in what he did. Also, bear in mind that even if your 4th amendment rights were violated, there probably is no monetary recovery (compensation) for that, though it may be the case that any evidence found as a result of the improper entry cann be suppressed.