Should I report a possible puppy mill?

Ask: I was at my friends boyfriends house about 6 months ago. It's a trashed out trailer and in the back there are cages and I think he said there are about 23 dogs back there. 

Anyway we went inside and he said there are 16 cats that live inside. 

It smelled horrible and the kitchen had caught on fire and was all black. Anyway should I call someone tell them that there may be some animal cruelty going on? 

I would have done it sooner but I didn't want my friends to be mad at me but we aren't really friends anymore so I thought maybe I should call. 

Not that I want them to get in trouble but that the animals need to be removed. Who do I call?

Answer

Samantha:  
Yes! That definatly seems like animal cruelty! They clearly have too many and keeping them in cages is not good for their health. Call the nearest animal control to take them to good loving homes. 

Heart Gold:  
Yes, absolutely you need to report this. To whom is the question. Obviously there are various law enforcement and animal control organizations who could get involved. I suggest reporting as anal cruelty rather than as a puppy mill. I would start by talking to the SPCA local chapter and if this isn't something they will investigate ask them who else you should contact. 

Knight:

Get evidence of your allegations in the form of photos/videos, date/time stamped, witnesses willing to come forward with the same evidence and then submit that evidence to the proper authorities, such as your local SPCA, Humane Society, Animal Control, don't bother the Police with this.

Narissa:
Of course, if you even suspect animals are being abused, neglected or otherwise mistreated you should intervene and get to the bottom of it. Better safe than sorry.