The name "Jack" was already used to describe another fabled London attacker: "Spring-heeled Jack", who supposedly leapt over walls to strike at his victims and escape as quickly as he came.
Navnet "Jack" blev allerede brugt til at beskrive en anden kendt London-karakter, Spring Heeled Jack, der efter sigende skulle hoppe over mure og angribe sine ofre, for så at forsvinde lige så hurtigt som han kom.