Does one who kills a guard dog that was given poison in the house fall under the warning of the Hadith: "Whoever looks into the house of a people..."? And is it true that a guard dog prevents angels from entering the house? And what is the religious punishment for its killer if known?

It is not permissible to kill a guard dog, and what the neighbors did is forbidden because it is not permissible to kill a dog that is allowed to be kept. Whoever kills it is an evildoer, an oppressor, and a sinner. There is no recompense or financial compensation due from the killer of a trained dog, according to the more preponderant opinion. Rather, it is recommended to kill it if it is a pure black dog, and it is obligatory to kill it if it is rabid or vicious.

The matter can be referred to the competent authorities for a decision.