I'm not certain that the git committer tells you the full story. I don't believe the AUR enforces that the git commit email is the same as the current maintainer email. So this could have been an orphan package, adopted by a malicious user, generated a malicious commit with the previous maintainer's git info.

Unfortunately, I don't see a way of viewing the ownership history of a package in the AUR. I know you get emails with ownership changes if you're subscribed to a package, but I don't see this info in the web interface anywhere.