Workaround for pulling all image comments by a user

Is there a way to see all of the comments a user has posted on an image?

We recently had a spammer post spam topics, comments on ideas, and comments on images. It seems the "mark all content as spam" function doesn't mark image comments as spam, and this information isn't included in a user's private stats. We want to find these comments so we can manually delete them.

Lithium Support said there aren't any outright calls in the API to get this sort of information, but that perhaps someone knew of a workaround.

Any help is appreciated! Thanks!