The People of the Book (Christians and Jews) have certain abrogating qualities distinguishing them from the rest, of those who don’t believe in Islam as message from God, by virtue of the fact that they are recipients of divine books even though these books have been changed.
Because of this distinguishing quality, Faith of Islam has specified special rulings particular to the People of the Book, and exceptions specific to them in some rulings, such the permissibility of eating their slaughtered meat, as indicated in the following ayah (interpretation of the meaning): : “This day are (all) things Good and pure made lawful unto you. The food of the People of the Book is lawful unto you and yours is lawful unto them. “ (Maa’ida: 5)
The preceding discussion is in regards to the general ruling with respect to slaughtered meat of the Halal animals – slaughtered by People of the Book: If the animal was not slaughter as it is known by the way specified by Islam, as is the case if he chokes it or electrocutes it until it dies or drowns it in water until it dies or kills it by a bullet, etc. In this case there is no doubt that eating it is forbidden since it is “maita” (meat of an animal that has died without properly being slaughtered) and Allah has forbidden it in the Qur’an (interpretation of the meaning): “… and forbidden unto you is maita “dead animals”…” (al-Maa’ida:3)…more: islamweb