Anderson claimed that the Ripper had been identified by the "only person who had ever had a good view of the murderer", but that no prosecution was possible because both the witness and the culprit were Jews and Jews were not willing to offer testimony against fellow Jews
Mesirah (or mesira, lit. 'to hand over') is the action in which one Jew reports the conduct of another Jew to a non-rabbinic authority in a manner and under the circumstances forbidden by rabbinic law
https://en.wikipedia.org/wiki/Mesirah
This is what the Orthodox kike text of Sanhedrin 57a says
With regard to bloodshed, if a gentile murders another gentile, or a gentile murders a Jew, he is liable. If a Jew murders a gentile, he is exempt.
https://www.sefaria.org/Sanhedrin.57a.16?lang=bi&with=all&lang2=en
Why Jack the ripper was not reported
