Derby4570: that's sort of like asking if the driver's license tester can be held liable for passing you on your driving test and then you have an accident later. An individual performing a legally required function, and performing it properly, can not be held accountable for the actions of others especially if they are not or no longer under that individual's control, if they ever were.
And, a question to you - who would attempt to hold the instructor liable and for what reason - a municipality, individual, advocate group, relative??. You didn't mention if it was a justifiable shooting or an illegal act. In either regard, the individual can be responsible only for themself and although you will surely have some idjits try holding individuals, companies, groups or manufacturers responsible for the misuse of a product or skills training, this effort has been defeated so many times that even the most liberal New York City judges toss these cases out. HTH. Mikey.