I'd reserve judgment on this. If he really committed armed robberies, as the report led the police to believe, then they would have expected him to be armed and dangerous, and might have mistaken what he held in his hand.
If he DIDN'T commit armed robberies, then whoever wrote the report needs to be disciplined. But I see no reason to disbelieve it.
I assume he had failed to appear on the charges, before a warrant authorizing a no-knock entry was issued. If you're charged with armed robbery and assault with a deadly weapon, you better show up in court or at the police station when summoned. If you don't, law enforcement will reasonably assume that you are in fact an individual who has committed armed robbery and assault with a deadly weapon, and who has subsequently shown contempt for the legal process. Accordingly, they will not assume you and your friends will behave like choir boys when they come to get you, and they will come to get you in a manner appropriate for fetching in deadly weapon-wielding felons.
I'm getting REALLY TIRED of cops saying they "thought" he had a gun so they took his life.....they need to determine that he has one or not....none of this excuse for shooting an unarmed person by saying they "thought" he was armed......