I would like to see the actual warrant. I am wondering if the address on the warrant was incorrect, or if the address was correct on the warrant and the agents hit the wrong house. It makes a dig difference as to who is at fault. Here's an example:
Let's say Billy Red is a bad guy who lives at 123 Main street. He commits a felony crime, police investigate, and swear out a warrant for his arrest. Mistakenly, a clerk types 132 Main street and no one notices. A magistrate signs the warrant and it goes to the warrant division. Mind you, the warrant division guys may not be familiar with specifics of the case. Guys from the warrant division go to 132 Main and since they have a felony warrant, they are allowed to breech the door.... to the wrong house.
Or it could be that Billy Red did not actually live at 123 Main Street at all, and the police got it wrong when they were swearing out the warrant.
Either way.... it's a sucky scenario.
I am wondering if it was just a search warrant or if it was a search & arrest warrant (there's a difference in Texas).
I am surprised they used a chainsaw. It is a slow way to breech a door. If forceable entry is justified in the first place, just kick it or use a battering ram. In this case, however, using a chain saw was beneficial since the door will be easy to replace.
By and large I am not a fan of the FBI. I have worked with them on several occasions and here is my take: F.B.I. = Famous But Incompetent.