Hello
The active participle from, say, קטל should be קָטֵל, of course, because that's the standard form. Examples from the Bible are כָּתֵב and אָמַר (in אָמַר the vowel changed to a patach because of the resh).
So, why is קָטוֹל used to mean "murderer" in the targums? Why is it not קָטֵל? Is...