Why can't I call Hawaii Police Department and file charges against a man who has been harassing me?

I live in SC and he live in Hawaii. I talked to the detective and he said that Hawaii will not prosecute him because the victim of the crime, me, lives in SC. He's been sexually harassing me over the phone since last summer. He's blocked his number so I didn't know who was calling. Now that I finally find out who it is, I can't file charges? It's because of jurisdiction issues the detective says. And he adds that, technically, it is a federal case but because it is a misdemeanor, the FBI won't do anything. He says the subpoenaed phone logs aren't enough. That he'll have to actually confess to the crime. That's a bunch of BS. Are there any loopholes I can walk through to get this done? Anyone had this happen to them before? Thanks.