I think the police became involved with Kosminski when a Mrs Kuer reported blood on some laundry at 22 Batty street. (Found by Rob House)
Kosminski was said to have lived in Germany for a few years before coming to England. So could probably speak German.
I found a German Mrs Kuhn lived at 22 Batty street in 1884 but Her daughter Caroline was born at 92 Sussex street, Poplar on 11th September 1888. They had also gone back to Frankfurt Germany in 1886 where her son was born.
Shame thought I found her.....
I found this part of the article interesting.
Could the woman that the man had previously lived with, be Woolfes wife Betsy? Maybe she did not want him to know who had reported him?
It also states that a few people mentioned the same man in Berner street area.
Although not proven, Kosminski could fit with this....It says he was placed under surveillance by the police .
However I must say it probably also fits other people too.