What implicates “Cohen?” Bonn points to the work of Ripper contemporary Dr. Thomas Bond, who (according to Casebook) was not present for the initial investigations but researched the case extensively. By the fall of 1888, Psychology Today goes on, Dr. Bond had seemingly identified the killer’s modus operandi: each of the women had their throat cut first, while laying prone, and they were seemingly murdered by the same person.

According to Thomas Bond, the killer wasn’t the medical expert many believe they may have been. Per Psychology Today, Bond considered him instead to be an antisocial man who was prone to violent, lustful outbursts. A “disorganized” murderer, in modern FBI profiling terms, who did not plan attacks but seized opportunities, often doing appalling damage to the bodies but rarely troubling to hide them. Bonn points out that a lot of this has come to be characteristic of the Ripper murders, along with the killer’s obvious hatred for the women he killed. 

Bonn states that Cohen was taken to Colney Hatch Lunatic Asylum shortly after the final (and most brutal) Ripper killing. The institution’s records seemingly confirm that Cohen had a murderous bent and despised women. Couple all of this with the fact that the FBI’s John Douglas (per Mindhunters) highlighted a suspect named Aaron Kosminski, a Jewish man from Poland who found himself in such an institution, and it’s another compelling theory. Kosminski could be Cohen, and Cohen could have been the killer.