Murder or not?

If I had a security device in my house which could kill the perpetrator and it would kill some random thief trying to burgle my house, would I be responsible for his death/murder?

I think if you post a sign stating "Death to all who enter with out permission" it will be o.k. at least in Texas

yes and no

Where I live if someone trespasses on your property and you kill them, it's legal because it's considered self defense. But if they trespass and become injured, they can sue. Screwy huh?

Your home is your castle, and you can defend your home with deadly force if you reasonably believe your safety or that of your family to be in danger.

You can never defend property with deadly force. Traps are in defense of property, not of person. They also do not discriminate, so there is no way to claim reasonable fear for safety.

Accordingly, it has been held that death traps make you civilly and criminally liable for someone's death.

Will be in some jurisdictions.

Yes. There are cases on exactly that and not only can you be charged with murder but his estate can also sue you. Deadly force is only allowed when you are in your home and a jury could reasonably believe that you feared for you or your family's safety. Even the castle doctrine doesn't allow for booby traps.

It is also illegal even if you have a warning sign.

EDIT: You would probably only be charged with murder 2 though or manslaughter.

Setting traps counts as murder in most jurisdictions no matter who you kill.

that would be a boobie trap and it is illegal to booby trap your home. You would be liable for any harm done

self defense is it not

You can't set up such a trap. It would be Murder, and you would also be subject to a Wrongful Death lawsuit from his estate/heirs.

You can have a guard dog, you can have a firearm, you can even use a baseball bat with nails driven through it, but you cannot set a trap that might just kill your neighbor who stumbles home drunk and gets the wrong house.

Yes

I'd have to say so. Because you're the one who set it in the first place causing that person to get killed.