Those pesky collective nouns

A copyediting associate has raised some questions about the use of "forensics." The easy part: "Forensics" is the collective noun that takes a singular verb, while "forensic" is the adjective, as in "forensic medicine."

So far, so good. But should the black bag of the practitioner be called a "forensic toolkit" or a "forensics toolkit"? The argument for the latter is that "forensic medicine" is a special type of medicine, but a toolkit is just a toolkit that happens to be filled with the tools used in the art.

The argument is appealing, but this way lies madness and I resolutely turn my back on it. Make the adjective "forensic" in all cases.