Walking into a crime scene......?

I called 6 hours before to schedule this showing, it was a bank approved short sale, the agent explained that tenants live there and gave me the keybox code.  I meet my clients at the property and struggle on getting the code, I must of written it down wrong, I call the agent he answers gives me the right code and lets me know that sometimes they deadbolt the top lock and if so I will have to go around back.  Get the key, head around back where a big "mean" looking dog is looking out at us.  Call the agent again (feeling a little foolish) ask him if the dog is nice?  He says, "I haven't had a problem or complaint" Fair enough, open the door, the dog is a big sweetheart, but..... in the kitchen I see a big, sturdy chair at the kitchen table absolutely destroyed and in pieces on the floor.  I'm thinking hmmm the dog must of done that, but I wonder how, big dog, but not long legs.  Then I see a coffee cup on the floor across the kitchen broken and in pieces, I'm thinking, wow the homeowners are not going to be happy with their animal.  Then I spot the blood drips all along the floor, I mention to my client the dog must be hurt who proceeds to check his paws and see's nothing.  I follow the trail of blood to the family room around the corner where there is a picture (wedding picture) on the floor with the glass shattered and the frame in pieces, I ask my client to put the dog in the laundry room while we finish showing the property so he doesn't cut himself further.  I am still thinking the dog went crazy being left at home and the blood is a cut from somewhere.  We proceed upstairs cautiously where in the Master Bedroom there is a pair of pants sitting on top of the laundry with a huge hole in the thigh (yes it looked like a stab mark) and blood all on the pants.  We proceed downstairs immediately when we hear the garage door open, I suggest we get out immediately since we don't know what happened here, so we let the dog out and leave through the back door.  I take my clients over to our cars where we see two guys get out of a truck go into the house, one comes back out and then they go back in.  I realize I need to put the key back in the key box which is on the front door handle that is wide open.  When I walk up the steps, the guy goes, "what happened here"  I told him, "I hoped he would know" he said he lives there but doesn't know, but seriously if you saw your house in that condition wouldn't you a- check upstairs and b- be on the phone with your wife seeing how she is?  Instead of working so hard at cleaning it up??  Maybe not, I had to call the agent again let him know the condition, which he laughed at me and said he will cover me if the tenants call and claim I stabbed a client in thier home.  Thanks a lot....  I did ask the agent to at least make sure every member of the family is okay.