Deleting a Bare Repo

I'd like to delete a bare git repo, but I want to check that (a) it's being used as the actual git bare repo, e.g. if $GIT_DIR is set, and (b) that it is actually a git repo. Using rm -rf .git/ doesn't seem safe for these reasons, so is there a command in git itself to do this?

I've been going through the man pages without success.