Jack the Ripper, the notorious serial killer who terrorized London over a century ago, has been identified as a Polish Jew, Aaron Kosminski, a resident of East London. The lead investigator's private notes on the investigation were released. In them, the investigator notes that Kosminski was positively identified by a witness, but the witness refused to give testimony, in part, it seems, because both Kosminski and the witness were Jewish.
[Hat tip: JWB.]