Police Procedure Questions

Okay, so I'm stuck until I can get accurate answers to a few questions. I have created a scene that demands the attention of local law enforcement. Here's the scenerio:

Important Fact #1: There are no dead bodies, but the entire family is missing.

Important Fact #2: There are bullet holes everywhere and signs of forced entry.

Important Fact #3: There is blood at the scene.

Important Fact #4: There is a car in the driveway with evidence of backing into a tree and a broken out driver's side window.

Important Fact #5: Said car does not belong to any of the family members.

Okay, given these facts, how would the police react/respond/investigate? Would this be considered a homicide scene or a treated more as a missing persons until a body shows up? Would the house be roped off? Would a detective be assigned to monitor the house?

Keep in mind this all takes place in a small town.