The police investigation is mentioned twice in the interview, i.e. "The police are investigating the case so I won’t be able to say much."
There are various new articles about the Tokyo Metropolitan Police and Mt.gox "working together", but it sounds like you are right that the police are not investigating Karpeles.
No one has heard anything about a police investigation into embezzlement or fraudulent behavior. Karpeles alludes to the police investigating "physical attacks". Surprise surprise, another excuse.
There are various new articles about the Tokyo Metropolitan Police and Mt.gox "working together", but it sounds like you are right that the police are not investigating Karpeles.