In "Seventy-Six Dollars," who is Lisa Castillo?

Lisa Castillo is a girl Monk met on a beach when he was eight. He was apparently attracted to her. He compares her to Angel Carter, noting that something about Angel reminded him of Lisa. It is significant, then, that Monk thinks the fact that Lisa threw sand in his eyes means she felt the same way about him that he felt about her. Somehow Monk has come to believe that girls who mistreat him actually like him.